Document Control

Field	Value
Document ID	admins-sandboxvars-reference
Version	1.0.0
Status	approved
Confidence	Medium
Category (track)	Admins
Build	both
Owner	PZ Knowledge-Base Pipeline
Created	2026-07-30
Updated	2026-10-08
Review due	2027-01-07
Game versions verified	41.78.16, 42.20, 42.21

Executive Summary

Every Project Zomboid server carries its gameplay rulebook in a single Lua file, <servername>_SandboxVars.lua, generated next to the server's .ini under Zomboid/Server in the hosting user's home directory [9]. Where the .ini decides how the server runs (ports, mods, security), SandboxVars decides how the game plays: zombie behaviour and population, loot rarity, XP rates, when the water and power die, how fast crops grow, what condition the cars are in. This document is the per-key reference for that file on both supported builds, sourced from two revision-pinned wiki listings — the 42.20-era listing for Build 42 [5] and the archived Build 41 listing [6] — corroborated where possible against official patch notes [1] [2] [3].

The two builds do not speak the same dialect. The B41 file is VERSION = 4 with a flat key set plus two nested tables; the 42.20 file is VERSION = 6 and both larger and re-scaled [5] [6]. The operationally dangerous deltas: the zombie population scale was renumbered (a "Normal" count is PopulationMultiplier = 0.65 on B42, where B41 used 1.0 [5] [6]), zombie respawn is zeroed out in the B42 generated defaults where B41 defaulted to respawn every 72 hours [5] [6], the B41 loot-rarity enums were replaced by per-category numeric multipliers, and the single B41 XpMultiplier became a per-skill MultiplierConfig table [5] [6]. Build 42 also adds whole new sandbox families — animals and vermin, basements, the in-game map, and firearm handling [5].

Document confidence is Medium: the B42 key set, defaults and ranges rest on a current, version-stamped wiki revision with several keys corroborated by official patch notes, but the B41 listing is an older example file whose enum comments conflict in places with the B41 sandbox-UI documentation, and no game-file diff has been run first-hand. Where the B41 evidence is thin this document says so instead of guessing.

Key Takeaways

• One file per server name — <servername>_SandboxVars.lua beside the .ini; the server generates it with defaults if missing, and mods' own sandbox options live in the same SandboxVars namespace (cited) (both)
• The B42 population scale is renumbered: Normal = 0.65, Insane = 2.5 (ZombieConfig.PopulationMultiplier), against B41's Normal = 1.0, Insane = 4.0 — never copy a B41 population number onto a B42 server (cited)
• The 42.20 generated file disables zombie respawn (ZombieRespawn = None; RespawnHours, RespawnUnseenHours, RespawnMultiplier all 0), where B41 defaulted to respawn every 72 hours — on B42 you must opt in (cited)
• Loot rarity moved from B41 enum steps (FoodLoot etc.) to ~21 per-category numeric multipliers (FoodLootNew etc., 0–4) plus six tier-factor keys (cited)
• XP tuning moved from the single XpMultiplier to MultiplierConfig with a Global value, a GlobalToggle, and ~35 per-skill keys using internal names (Woodwork = Carpentry, Doctor = First Aid, PlantScavenging = Foraging) (cited) (B42)
• Basements are sandbox-controlled on B42 — Basement.SpawnFrequency — and animals/wildlife get a 16-key family (cited) (B42)
• Several options migrated from server.ini into SandboxVars between builds, including MinutesPerPage, HoursForCorpseRemoval and the loot-respawn trio (cited)
• Whether SandboxVars edits can be applied without a full server stop is contested; only a .ini live-reload path is documented — see the quarantined discussion in admins-foundation (community, unverified)

Purpose

This is the Admins-track key reference for the gameplay half of server configuration. It answers: which key controls a given rule, what type and range it accepts, what the generated default is on each build, which keys exist on only one build, and which popular values are folklore rather than documented fact. It exists so an admin can edit servertest_SandboxVars.lua with a text editor and a citation, instead of a half-remembered B41 guide.

Scope

Covered: every key present in the two revision-pinned SandboxVars listings — the full 42.20-era file documented at wiki revision 1443167 [5] and the flat-plus-nested key set in the archived B41-era revision 1393223 [6] — organized by area: population, zombie lore, loot, XP and character, world clock and utilities, nature and farming, vehicles, and the B42-only families (animals/wildlife, basements, map, firearms). Where a rule is exposed in the B41 sandbox UI but its Lua key is not pinned by a cited listing, that gap is stated, not papered over.

Not covered: the server.ini key set (see admins-server-ini-reference), spawnpoint/spawnregion Lua files, RCON/admin command operations, mod-defined sandbox options beyond how they attach to this file, and per-key gameplay deep-dives (the Players track owns mechanic behaviour). The B41 column documents the archived listing as-is; it is not a first-hand dump of a 41.78.16 install.

Definitions

• SandboxVars — the Lua table serialized in <servername>_SandboxVars.lua; the server's gameplay-rule settings, distinct from the .ini server settings [5] [9].
• Enum (coded option) — a multiple-choice option stored as a 1-based integer code; the meaning of each code is fixed per key (e.g. ZombieLore.Speed code 1 means Sprinters) [5].
• ZombieLore — the nested table of zombie behaviour settings (speed, strength, transmission, senses) [5] [6].
• ZombieConfig — the nested table of population-model settings (multipliers, respawn, grouping) [5] [6].
• MultiplierConfig — the B42-only nested table of XP multipliers, one key per skill plus a global pair [5].
• VERSION — the schema stamp at the top of the file; the game uses it to migrate older files. It is 4 in the archived B41 listing and 6 in the 42.20 listing [5] [6].
• Generated default — the value the server writes when it creates the file itself; defaults quoted in this document are the 42.20 generated values unless tagged otherwise [5] [9].

Build Applicability

Build	Applies	Verified against	Notes
B41 (legacy41)	Yes	Archived wiki listing, page versioned 41.78.19 [6]; B41 sandbox-UI docs [7]	Served from the legacy41 branch since 42.20 went stable [4]; B41-only keys tagged (B41)
B42 (stable)	Yes	Wiki revision versioned 42.20.0 [5]; 42.20.1-42.21 patch notes reviewed [10] [11] [12]	Key names corroborated in official 42.17–42.20 patch notes [1] [2] [3]; B42-only keys tagged (B42); 42.21 has been stable since 2026-09-28 [11]

42.21 re-check scope. Re-checked: the official 42.21 unstable and stable Steam notes [10] [11] and the TIS forum 42.21 changelist [12] were read for any SandboxVars key, default or range change; none is named in them, and the 42.20.1-42.20.4 hotfix notes were also read with the same result. Not re-checked: the key list, defaults and ranges are still the wiki rendering at revision 1443167 [5] and were not re-extracted from a 42.21 server install. Everything not mentioned below is carried forward from 42.20 with no contradicting change found, not re-tested.

The B42 listing is version-stamped 42.20.0 [5]. The B41 listing is an archived page revision whose SandboxVars block carries VERSION = 4 and some enum comments that disagree with the B41 sandbox-UI documentation [6] [7]; treat its enum numbering as indicative, and its key names as the reliable part.

Reference

The file: location, generation, and shape

The file lives at %USERPROFILE%\Zomboid\Server (Windows) or ~/Zomboid/Server (Linux), named after the server (servertest_SandboxVars.lua by default), and is plain-text editable [9]. If it is absent at startup, the server writes one with default values [9]. Live values can be inspected with the showoptions admin command; the documented live-reload path (reloadoptions) is described for the .ini only [9]. The file is a single Lua assignment, SandboxVars = { ... }, opening with the schema stamp VERSION — 4 in the archived B41 listing, 6 at 42.20 [5] [6]. Most keys sit at the top level; behaviour families nest in sub-tables (ZombieLore, ZombieConfig, and on B42 also Map, Basement, MultiplierConfig), which this document writes in dotted form, e.g. ZombieLore.Speed [5] [6]. Mods extend the same namespace: a mod's sandbox-options.txt defines option ModName.OptionName entries that are read and written as SandboxVars.ModName.OptionName, with types boolean, integer, double, string and enum [8]. Enum options are stored as 1-based integer codes [5] [8].

Recurring coded scales, abbreviated in the tables below (codes in parentheses) [5]:

Scale	Coded values
S-FREQ6	Never (1), Extremely Rare (2), Rare (3), Sometimes (4), Often (5), Very Often (6)
S-STORY7	S-FREQ6 plus Always Tries (7)
S-RATE5	Very Fast (1), Fast (2), Normal (3), Slow (4), Very Slow (5)
S-ANIM6	Ultra Fast (1), then S-RATE5 as codes 2–6
S-LEVEL5	Very Low (1), Low (2), Normal (3), High (4), Very High (5)
S-ABUND5	Very Poor (1), Poor (2), Normal (3), Abundant (4), Very Abundant (5)

Column key for all tables in this section: Default is the 42.20 generated value [5] unless the Build column says B41, in which case it comes from the archived listing [6] or the B41 UI docs [7]; Build states where the key name is pinned by a cited listing.

Top-level control and the population dial

The quick population controls sit at the top of the file; the fine-grained model lives in ZombieConfig below [5] [6].

Key	Type	Default	Range / coded values	Build	Notes
VERSION	integer	6	schema stamp	both	4 in the archived B41 listing [6]; do not hand-edit
Zombies	enum	4	codes 1–6, most to none: Insane, Very High, High, Normal, Low, None	both	Sets the population preset; archived B41 comment describes a five-step scale [6], the B41 UI shows six counts [7]
Distribution	enum	1	Urban Focused (1), Uniform (2)	both	Where the population concentrates [5] [6]
ZombieVoronoiNoise	boolean	true	true/false	B42	Adds randomization to the distribution pattern [5]
ZombieRespawn	enum	4	High (1), Normal (2), Low (3), None (4)	B42	Master respawn preset; generated default is None [5]
ZombieMigrate	boolean	true	true/false	B42	Lets zombies drift into empty cells [5]

Dynamic population: ZombieConfig

42.21 note (B42). The 42.21 notes record fixes for zombies disappearing after a player left and re-entered a chunk (single-player and multiplayer) and for several zombie-duplication cases in multiplayer; the stable announcement says some instances remain and are slated for the next update [10] [11] [12]. These are behaviour fixes: the notes change no population or respawn key, so the tables below are unchanged.

The multiplier-to-preset mappings differ per build. On B42 a Normal count is 0.65, with Low at 0.15, High at 1.2, Very High at 1.6, Insane at 2.5 and None at zero [5]; on B41 a Normal count is 1.0, with Low at 0.35, High at 2.0, Insane at 4.0 and None at zero [6] [7].

Key	Type	Default	Range / coded values	Build	Notes
ZombieConfig.PopulationMultiplier	double	0.65	0–4	both	B41 default 1.0 [6] [7]; scale renumbered on B42 [5]
ZombieConfig.PopulationStartMultiplier	double	1.0	0–4	both	Day-one population scaling [5] [6]
ZombieConfig.PopulationPeakMultiplier	double	1.5	0–4	both	Population scaling at the peak day [5] [6]
ZombieConfig.PopulationPeakDay	integer	28	1–365	both	In-game day the population crests [5] [6]
ZombieConfig.RespawnHours	double	0.0	0–8760	both	Hours between respawn waves per cell; 0 disables. B41 default 72 [6] [7]
ZombieConfig.RespawnUnseenHours	double	0.0	0–8760	both	Chunk must go unseen this long first. B41 default 16 [6] [7]
ZombieConfig.RespawnMultiplier	double	0.0	0–1	both	Fraction of a cell's target population returned per wave. B41 default 0.1 [6] [7]
ZombieConfig.RedistributeHours	double	12.0	0–8760	both	Intra-cell migration interval; 0 disables [5] [6]
ZombieConfig.FollowSoundDistance	integer	100	10–1000	both	How far a zombie walks toward the last heard sound [5] [6]
ZombieConfig.RallyGroupSize	integer	20	0–1000	both	Idle group size; 0 = no grouping; none indoors or in forest zones [5] [6]
ZombieConfig.RallyGroupSizeVariance	integer	50	0–100	B42	Percent spread around the group size [5]
ZombieConfig.RallyTravelDistance	integer	20	5–50	both	Distance travelled to join a group [5] [6]
ZombieConfig.RallyGroupSeparation	integer	15	5–25	both	Spacing between groups [5] [6]
ZombieConfig.RallyGroupRadius	integer	3	1–10	both	Cohesion around the group leader [5] [6]
ZombieConfig.ZombiesCountBeforeDelete	integer	300	0–5000	B42	Cleanup threshold; in-file warning to keep the default; ceiling raised from 500 to 5000 at 42.20 [1] [5]

Zombie behaviour: ZombieLore

B42 defaults lean on randomness: Speed and Toughness default to Random, Sight and Hearing to a Normal-to-Poor random band [5], where the B41 Apocalypse preset used fixed Fast Shamblers / Normal senses [7].

Key	Type	Default	Range / coded values	Build	Notes
ZombieLore.Speed	enum	4	Sprinters (1), Fast Shamblers (2), Shamblers (3), Random (4)	both	Archived B41 comment lists only codes 1–3 [6]; the B41 UI includes Random [7]
ZombieLore.SprinterPercentage	integer	0	0–100	B42	Share of sprinters when Speed is Random [5]
ZombieLore.Strength	enum	2	Superhuman (1), Normal (2), Weak (3), Random (4)	both	Attack damage and skin-break odds [5] [6]
ZombieLore.Toughness	enum	4	Tough (1), Normal (2), Fragile (3), Random (4)	both	Kill difficulty [5] [6]
ZombieLore.Transmission	enum	1	Blood and Saliva (1), Saliva Only (2), Everyone's Infected (3), None (4)	both	Knox Event vector; code 3 reanimates every death [5] [6]
ZombieLore.Mortality	enum	5	Instant (1) through 1–2 Weeks (6), Never (7)	both	Time for infection to kill; archived B41 comment shows six codes, the B41 UI also lists Never [6] [7]
ZombieLore.Reanimate	enum	3	Instant (1) through 1–2 Weeks (6)	both	Corpse-rise delay [5] [6]
ZombieLore.Cognition	enum	3	Navigate and Use Doors (1), Navigate (2), Basic Navigation (3), Random (4)	both	Pathing intelligence [5] [6]
ZombieLore.DoorOpeningPercentage	integer	0	0–100	B42	Share of door-capable zombies [5]
ZombieLore.CrawlUnderVehicle	enum	5	Crawlers Only (1), then S-FREQ6-style codes 2–6, Always (7)	B42	B41 UI exposes the same option; Lua key not pinned for B41 [5] [7]. An "always" bug was fixed in 42.17 [3]
ZombieLore.Memory	enum	2	Long (1), Normal (2), Short (3), None (4), Random (5), Random Normal-to-None (6)	both	B41 listing covers codes 1–4 only [5] [6]
ZombieLore.Sight	enum	5	Eagle (1), Normal (2), Poor (3), Random (4), Random Normal-to-Poor (5)	both	B41 listing covers codes 1–3 [5] [6]
ZombieLore.Hearing	enum	5	Pinpoint (1), Normal (2), Poor (3), Random (4), Random Normal-to-Poor (5)	both	B41 listing covers codes 1–3 [5] [6]
ZombieLore.Smell	enum	—	Bloodhound (1), Normal (2), Poor (3)	B41	Absent from the 42.20 listing [5] [6]
ZombieLore.Decomp	enum	—	Slows and weakens (1) through No Effect (4)	B41	Decomposition effect; absent from the 42.20 listing [5] [6]
ZombieLore.SpottedLogic	boolean	true	true/false	B42	Advanced stealth/visibility model [5]
ZombieLore.ThumpNoChasing	boolean	false	true/false	both	Idle zombies attack doors/constructions [5] [6]
ZombieLore.ThumpOnConstruction	boolean	true	true/false	both	Player builds can be damaged [5] [6]
ZombieLore.ActiveOnly	enum	1	Both (1), Night (2), Day (3)	both	When zombies are at full activity [5] [6]
ZombieLore.TriggerHouseAlarm	enum-or-bool	true	true/false	both	42.20 file has it on; the B41 UI documents it default-off [5] [7]
ZombieLore.ZombiesDragDown	boolean	true	true/false	both	Group drag-down kills [5] [6]
ZombieLore.ZombiesCrawlersDragDown	boolean	false	true/false	B42	Crawlers count toward drag-down [5]
ZombieLore.ZombiesFenceLunge	boolean	true	true/false	both	Post-climb lunge [5] [6]
ZombieLore.ZombiesArmorFactor	double	2.0	0–100	B42	Effectiveness multiplier for zombie-worn protection [5]
ZombieLore.ZombiesMaxDefense	integer	85	0–100	B42	Cap on zombie garment defense percent [5]
ZombieLore.ChanceOfAttachedWeapon	integer	6	0–100	B42	Percent with a holstered/attached item [5]
ZombieLore.ZombiesFallDamage	double	1.0	0–100	B42	Fall-damage multiplier for zombies [5]
ZombieLore.DisableFakeDead	enum	1	World Zombies (1), World and Combat Zombies (2), Never (3)	B42	Which "playing dead" zombies exist; B41 UI has a three-way equivalent [5] [7]
ZombieLore.PlayerSpawnZombieRemoval	enum	1	Building and surroundings (1), Building (2), Room (3), Anywhere (4)	B42	Spawn-safety clearing [5]
ZombieLore.FenceThumpersRequired	integer	25	-1–100	B42	Zombies needed to damage a tall fence [5]
ZombieLore.FenceDamageMultiplier	double	1.0	0.01–100	B42	Tall-fence damage rate [5]

Loot rarity and the world loot state

Build 41 stored loot rarity as enum steps; the archived listing shows FoodLoot, WeaponLoot and OtherLoot with a rare-to-abundant comment scale [6], and the B41 UI documents seven steps (None through Abundant) across ten categories [7]. Build 42 replaces this with per-category numeric multipliers (0–4, higher = more) plus six tier-factor keys that define what each named rarity tier means numerically [5].

Key	Type	Default	Range / coded values	Build	Notes
FoodLoot	enum	—	rare (1) to abundant (5) per archived comment; the B41 UI shows 7 steps	B41	Perishable food [6] [7]
WeaponLoot	enum	—	as FoodLoot	B41	Weapons [6] [7]
OtherLoot	enum	—	as FoodLoot	B41	Everything uncategorized [6] [7]
LootRespawn	enum	—	None (1), Every Day (2), Every Week (3), Every Month (4), Every Two Months (5)	B41	All presets default None [6] [7]
FoodLootNew	double	0.8	0–4	B42	Perishable food [5]
CannedFoodLootNew	double	0.6	0–4	B42	Canned/dried food and drink [5]
LiteratureLootNew	double	0.6	0–4	B42	Readables other than skill books [5]
SkillBookLoot	double	0.6	0–4	B42	XP-multiplier books [5]
RecipeResourceLoot	double	0.6	0–4	B42	Recipe-teaching items [5]
MedicalLootNew	double	0.6	0–4	B42	First-aid items [5]
SurvivalGearsLootNew	double	0.6	0–4	B42	Camping/outdoor gear [5]
WeaponLootNew	double	0.6	0–4	B42	Melee weapons not in other tool families [5]
RangedWeaponLootNew	double	1.2	0–4	B42	Firearms and attachments [5]
AmmoLootNew	double	0.6	0–4	B42	Ammo, boxes, magazines [5]
MechanicsLootNew	double	0.6	0–4	B42	Vehicle parts and their tools [5]
ClothingLootNew	double	0.6	0–4	B42	Non-container wearables [5]
ContainerLootNew	double	0.6	0–4	B42	Bags and wearable containers [5]
KeyLootNew	double	0.4	0–4	B42	Keys, key rings, locks [5]
MediaLootNew	double	0.6	0–4	B42	Tapes and discs [5]
MementoLootNew	double	0.6	0–4	B42	Collectibles and keepsakes [5]
CookwareLootNew	double	0.6	0–4	B42	Cooking implements [5]
MaterialLootNew	double	0.6	0–4	B42	Crafting/building ingredients [5]
FarmingLootNew	double	0.6	0–4	B42	Agriculture items [5]
ToolLootNew	double	0.6	0–4	B42	General tools [5]
OtherLootNew	double	0.8	0–4	B42	Fallback category; also scales Town/Road-zone foraging [5]
InsaneLootFactor	double	0.05	0–0.2	B42	Numeric meaning of the Insanely Rare tier [5]
ExtremeLootFactor	double	0.2	0.05–0.6	B42	Extremely Rare tier [5]
RareLootFactor	double	0.6	0.2–1	B42	Rare tier [5]
NormalLootFactor	double	1.0	0.6–2	B42	Normal tier [5]
CommonLootFactor	double	2.0	1–3	B42	Common tier [5]
AbundantLootFactor	double	3.0	2–4	B42	Abundant tier [5]
RollsMultiplier	double	1.0	0.1–100	B42	Loot-table roll count; in-file warning: leave alone, performance-sensitive [5]
LootItemRemovalList	string	""	comma-separated item types	B42	Items barred from ordinary loot [5]
RemoveStoryLoot	boolean	false	true/false	B42	Extends the bar to world stories [5]
RemoveZombieLoot	boolean	false	true/false	B42	Extends the bar to zombie-carried loot [5]
ZombiePopLootEffect	integer	0	0–20	B42	Scales loot up with nearby zombie density [5]
SeenHoursPreventLootRespawn	integer	0	0 to max int	both	Blocks respawn in recently seen zones; a B41 UI option, pinned as a sandbox key at 42.20 [5] [7]
HoursForLootRespawn	integer	0	0 to max int	both	Hours before looted town containers refill; 0 = never. A server.ini key on B41 [5] [6]
MaxItemsForLootRespawn	integer	5	0 to max int	both	Containers at or above this count are skipped. A server.ini key on B41 (default 4) [5] [6]
ConstructionPreventsLootRespawn	boolean	true	true/false	both	Player-built/barricaded buildings excluded. A server.ini key on B41 [5] [6]
MaximumLooted	integer	25	0–200	B42	Chance a found building spawns pre-looted [5]
DaysUntilMaximumLooted	integer	90	0–3650	B42	Ramp time for the pre-looted chance [5]
RuralLooted	double	0.5	0–2	B42	Pre-looted scaling for rural buildings [5]
MaximumDiminishedLoot	integer	20	0–100	B42	Peak percentage of loot withheld over time [5]
DaysUntilMaximumDiminishedLoot	integer	3650	0–3650	B42	Ramp time for diminished loot [5]
MaximumLootedBuildingRooms	integer	50	0–200	B42	Buildings larger than this are never pre-looted [5]

XP and character progression

Build 41 tunes XP with one key; Build 42 tunes it per skill. The B42 MultiplierConfig skill keys are internal identifiers, several of which differ from the UI skill names — the notes column gives the display name where they differ [5]. The B41 UI also documents an "XP Multiplier Affects Passive Skills" toggle (default off) whose Lua key is not present in the archived listing, so it is deliberately not tabled here [6] [7].

Key	Type	Default	Range / coded values	Build	Notes
XpMultiplier	double	1	0.001–1000	B41	Single global XP rate [6] [7]
MultiplierConfig.Global	double	1.0	0–1000	B42	Whole-game XP rate [5]
MultiplierConfig.GlobalToggle	boolean	true	true/false	B42	When true, Global overrides the per-skill keys [5]
MultiplierConfig.Fitness	double	1.0	0–1000	B42	Passive: Fitness [5]
MultiplierConfig.Strength	double	1.0	0–1000	B42	Passive: Strength [5]
MultiplierConfig.Sprinting	double	1.0	0–1000	B42	[5]
MultiplierConfig.Lightfoot	double	1.0	0–1000	B42	Display name: Lightfooted [5]
MultiplierConfig.Nimble	double	1.0	0–1000	B42	[5]
MultiplierConfig.Sneak	double	1.0	0–1000	B42	Display name: Sneaking [5]
MultiplierConfig.Axe	double	1.0	0–1000	B42	[5]
MultiplierConfig.Blunt	double	1.0	0–1000	B42	Display name: Long Blunt [5]
MultiplierConfig.SmallBlunt	double	1.0	0–1000	B42	Display name: Short Blunt [5]
MultiplierConfig.LongBlade	double	1.0	0–1000	B42	[5]
MultiplierConfig.SmallBlade	double	1.0	0–1000	B42	Display name: Short Blade [5]
MultiplierConfig.Spear	double	1.0	0–1000	B42	[5]
MultiplierConfig.Maintenance	double	1.0	0–1000	B42	[5]
MultiplierConfig.Woodwork	double	1.0	0–1000	B42	Display name: Carpentry [5]
MultiplierConfig.Cooking	double	1.0	0–1000	B42	[5]
MultiplierConfig.Farming	double	1.0	0–1000	B42	Display name: Agriculture [5]
MultiplierConfig.Doctor	double	1.0	0–1000	B42	Display name: First Aid [5]
MultiplierConfig.Electricity	double	1.0	0–1000	B42	Display name: Electrical [5]
MultiplierConfig.MetalWelding	double	1.0	0–1000	B42	Display name: Welding [5]
MultiplierConfig.Mechanics	double	1.0	0–1000	B42	[5]
MultiplierConfig.Tailoring	double	1.0	0–1000	B42	[5]
MultiplierConfig.Aiming	double	1.0	0–1000	B42	[5]
MultiplierConfig.Reloading	double	1.0	0–1000	B42	[5]
MultiplierConfig.Fishing	double	1.0	0–1000	B42	[5]
MultiplierConfig.Trapping	double	1.0	0–1000	B42	[5]
MultiplierConfig.PlantScavenging	double	1.0	0–1000	B42	Display name: Foraging [5]
MultiplierConfig.FlintKnapping	double	1.0	0–1000	B42	Display name: Knapping [5]
MultiplierConfig.Masonry	double	1.0	0–1000	B42	[5]
MultiplierConfig.Pottery	double	1.0	0–1000	B42	[5]
MultiplierConfig.Carving	double	1.0	0–1000	B42	[5]
MultiplierConfig.Husbandry	double	1.0	0–1000	B42	Display name: Animal Care [5]
MultiplierConfig.Tracking	double	1.0	0–1000	B42	[5]
MultiplierConfig.Blacksmith	double	1.0	0–1000	B42	Display name: Blacksmithing [5]
MultiplierConfig.Butchering	double	1.0	0–1000	B42	[5]
MultiplierConfig.Glassmaking	double	1.0	0–1000	B42	[5]
LevelForMediaXPCutoff	integer	3	0–10	B42	Skill level at which TV/VHS/media XP stops [5]
LevelForDismantleXPCutoff	integer	0	0–10	B42	Level at which furniture-scrapping XP stops; Electrical exempt [5]
StatsDecrease	enum	3	S-RATE5	both	Hunger/thirst/fatigue drain [5] [6]
EndRegen	enum	3	S-RATE5	both	Endurance recovery [5] [6]
StarterKit	boolean	false	true/false	both	Spawn kit: bag, bat, hammer, water, chips [5] [6]
Nutrition	boolean	true	true/false	both	Food nutrition affects the body; off freezes weight change [5] [6]
CharacterFreePoints	integer	0	-100–100	B42	Extra creation points; B41 UI equivalent is "Free Traits" [5] [7]
ConstructionBonusPoints	enum	3	S-LEVEL5	B42	Hit points of player builds; B41 UI equivalent exists [5] [7]
InjurySeverity	enum	2	Low (1), Normal (2), High (3)	B42	Injury impact and healing time [5] [7]
BoneFracture	boolean	true	true/false	B42	Fractures from falls/impacts/zombies [5] [7]
ClothingDegradation	enum	3	Disabled (1), Slow (2), Normal (3), Fast (4)	B42	Wear, dirt and blood on clothing [5] [7]
RearVulnerability	enum	3	Low (1), Medium (2), High (3)	B42	Bite odds from behind [5] [7]
MultiHitZombies	boolean	false	true/false	B42	Melee swings can strike several targets; B41 UI equivalent exists [5] [7]
AttackBlockMovements	boolean	true	true/false	B42	Swinging slows movement; B41 UI equivalent exists [5] [7]
AllClothesUnlocked	boolean	false	true/false	B42	Full wardrobe at creation; the B41 UI documents its equivalent default-on [5] [7]
EnablePoisoning	enum	1	True (1), False (2), Bleach only disabled (3)	B42	Food poisoning rules; B41 UI equivalent exists [5] [7]
NegativeTraitsPenalty	enum	1	None (1) to a per-trait penalty (4)	B42	Diminishing returns on negative-trait points [5]
MinutesPerPage	double	2.0	0–60	both	Reading speed per skill-book page; a server.ini key on B41 (default 1.0) [5] [6]
LiteratureCooldown	integer	45	1–365	B42	Days before re-reading gives benefits again [5]
MuscleStrainFactor	double	0.7	0–10	B42	Muscle-strain multiplier [5]
DiscomfortFactor	double	0.8	0–10	B42	Worn-item discomfort multiplier [5]
WoundInfectionFactor	double	1.0	0–10	B42	Wound-infection damage scaling; the 42.20 notes rebalance it (as "WouldInfectionFactor") for the Extinction preset [1] [5]
EasyClimbing	boolean	false	true/false	B42	Removes climb-failure chances [5]
NoBlackClothes	boolean	true	true/false	B42	Keeps random clothing tints out of near-black [5]

World clock, utilities shut-off, and world events

Key	Type	Default	Range / coded values	Build	Notes
DayLength	enum	4	27 codes: 15 min (1), 30 min (2), 1 h (3), 1 h 30 (4), then hourly to 23 h, Real-time (27)	both	42.20 default is 1 h 30 [5]; the archived B41 comment shows a nine-step scale ending in real-time [6]
StartYear	integer	1	1 = first year	both	[5] [6]
StartMonth	enum	7	January (1) to December (12)	both	July default; affects weather, foraging, farming [5] [6] [7]
StartDay	integer	9	day of month	both	[5] [6]
StartTime	enum	2	7 AM (1), 9 AM (2), 12 PM (3), 2 PM (4), 5 PM (5), 9 PM (6), 12 AM (7), 2 AM (8), 5 AM (9)	both	[5] [6]
DayNightCycle	enum	1	Normal (1), Endless Day (2), Endless Night (3)	B42	Clock override [5]
ClimateCycle	enum	1	Normal (1), No Weather (2), Endless Rain (3), Endless Storm (4), Endless Snow (5), Endless Blizzard (6)	B42	Weather override [5]
FogCycle	enum	1	Normal (1), No Fog (2), Endless Fog (3)	B42	Fog override [5]
NightLength	enum	3	Always Night (1), Long (2), Normal (3), Short (4), Always Day (5)	B42	Dusk-to-dawn span [5]
NightDarkness	enum	3	Pitch Black (1), Dark (2), Normal (3), Bright (4)	B42	Ambient night light; B41 UI equivalent exists [5] [7]
WaterShut	enum	2	Instant (1), 0–30 d (2), 0–2 m (3), 0–6 m (4), 0–1 y (5), 0–5 y (6), 2–6 m (7), 6–12 m (8), Disabled (9)	both	Plumbing cutoff window; Disabled (9) is B42-listed [5] [6]
ElecShut	enum	2	Instant (1), 14–30 d (2), then 14-day-floored windows to 5 y (6), 2–6 m (7), 6–12 m (8), Disabled (9)	both	Grid cutoff; the B42 windows start at day 14 [5] [6]
WaterShutModifier	integer	14	-1 to max int	both	Day offset for the water cutoff; archived B41 comment reads it as days-until-shutoff, -1 = instant [5] [6]; key named in the 42.17 notes [3]
ElecShutModifier	integer	14	-1 to max int	both	As above for electricity [5] [6]; key named in the 42.17 notes [3]
AlarmDecay	enum	2	Instant (1), 0–30 d (2), 0–2 m (3), 0–6 m (4), 0–1 y (5), 0–5 y (6)	B42	How long alarm batteries outlive the grid [5]
AlarmDecayModifier	integer	14	-1 to max int	B42	Day offset for alarm decay [5]
TimeSinceApo	enum	1	0 months (1) through 12 months (13)	both	World age at start; drives starting erosion and food age [5] [6] [7]
Alarm	enum	4	S-FREQ6	both	Burglar-alarm frequency on break-ins [5] [6]
LockedHouses	enum	6	S-FREQ6	both	Locked-door frequency [5] [6]
FoodRotSpeed	enum	3	S-RATE5	both	Spoilage rate [5] [6]
FridgeFactor	enum	3	S-LEVEL5 plus No Decay (6)	both	Refrigeration strength; code 6 is B42-listed [5] [6]
DaysForRottenFoodRemoval	integer	-1	-1 to max int	B42	Rotten-food cleanup; -1 keeps it forever; B41 UI equivalent exists [5] [7]
FireSpread	boolean	true	true/false	B42	Fire propagation; B41 UI equivalent exists [5] [7]
HoursForWorldItemRemoval	double	24.0	0 to max int	B42	Ground-item cleanup age; applies on chunk load [5]
WorldItemRemovalList	string	"Base.Hat,Base.Glasses,Base.Maggots,Base.Slug,Base.Slug2,Base.Snail,Base.Worm,Base.Dung_Mouse,Base.Dung_Rat"	comma-separated item types	B42	Cleanup list; the B41 UI documents a three-item default [5] [7]
ItemRemovalListBlacklistToggle	boolean	false	true/false	B42	Inverts the list into a keep-list [5]
HoursForCorpseRemoval	double	216.0	-1 to max int	B42	Corpse cleanup; at 0 no maggots spawn; formerly a server option per the B41 UI docs [5] [7]
DecayingCorpseHealthImpact	enum	3	None (1), Low (2), Normal (3), High (4), Insane (5)	B42	Corpse-sickness pressure; B41 UI equivalent has four steps [5] [7]
ZombieHealthImpact	boolean	false	true/false	B42	Extends corpse sickness to nearby active zombies [5]
BloodLevel	enum	3	None (1), Low (2), Normal (3), High (4), Ultra Gore (5)	B42	Gore decals; B41 UI equivalent exists [5] [7]
BloodSplatLifespanDays	integer	0	0–365	B42	Blood cleanup age; 0 = permanent [5]
MaggotSpawn	enum	1	In and Around Bodies (1), In Bodies Only (2), Never (3)	B42	B41 UI equivalent exists [5] [7]
Helicopter	enum	2	Never (1), Once (2), Sometimes (3), Often (4)	both	Event-zone flyovers [5] [6] [7]
MetaEvent	enum	2	Never (1), Sometimes (2), Often (3)	both	Off-screen sound events; the B41 UI shows a four-step list including Once [5] [7]
SleepingEvent	enum	1	Never (1), Sometimes (2), Often (3)	both	Night events while sleeping [5] [7]
GeneratorSpawning	enum	4	None (1), Insanely Rare (2), Extremely Rare (3), Rare (4), Normal (5), Common (6), Abundant (7)	both	42.20 uses a rarity scale; the B41 UI shows a frequency scale defaulting Sometimes [5] [7]
GeneratorFuelConsumption	double	0.1	0–100	both	Fuel burn per hour; the B41 UI documents default 1 [5] [7]
AllowExteriorGenerator	boolean	true	true/false	both	Generators power exterior tiles (gas pumps) [5] [7]
GeneratorTileRange	integer	20	1–100	B42	Horizontal supply radius [5]
GeneratorVerticalPowerRange	integer	3	1–15	B42	Floors served above and below [5]
LightBulbLifespan	double	2.0	0–1000	B42	Bulb life scaling; 0 = unbreakable; the B41 UI documents default 1.0 [5] [7]
SurvivorHouseChance	enum	3	S-STORY7	B42	Randomized-building stories; B41 UI equivalent uses S-FREQ6 [5] [7]
VehicleStoryChance	enum	3	S-STORY7	B42	Road stories such as roadblocks [5] [7]
ZoneStoryChance	enum	3	S-STORY7	B42	Zone stories such as forest camps [5] [7]
AnnotatedMapChance	enum	4	S-FREQ6	both	Survivor-annotated maps [5] [7]
MetaKnowledge	enum	3	Fully revealed (1), Shown as unknown (2), Completely hidden (3)	B42	Display of unseen media content [5]
SeeNotLearntRecipe	boolean	true	true/false	B42	Station menus show unlearnt recipes [5]
MaximumFireFuelHours	integer	8	1–168	B42	Fuel cap for campfires and stoves [5]
EnableTaintedWaterText	boolean	true	true/false	both	Tainted-water tooltip; a display bug against this option was fixed in 42.19 [2] [5] [7]
EnableSnowOnGround	boolean	true	true/false	both	Ground snow accumulation [5] [7]
MaxFogIntensity	enum	1	Normal (1), Moderate (2), Low (3), None (4)	both	Code 4 is B42-listed [5] [7]
MaxRainFxIntensity	enum	1	Normal (1), Moderate (2), Low (3)	both	Visual rain cap [5] [7]
Temperature	enum	3	Very Cold (1), Cold (2), Normal (3), Hot (4), Very Hot (5)	both	Global climate offset [5] [6]
Rain	enum	3	Very Dry (1), Dry (2), Normal (3), Rainy (4), Very Rainy (5)	both	Rainfall amount [5] [6]

Nature, farming, and erosion

Key	Type	Default	Range / coded values	Build	Notes
ErosionSpeed	enum	4	Very Fast 20 d (1), Fast 50 d (2), Normal 100 d (3), Slow 200 d (4), Very Slow 500 d (5)	both	Days to full overgrowth; 42.20 file ships Slow [5] [6]
ErosionDays	integer	0	-1–36500	B42	Exact-day override; 0 defers to ErosionSpeed [5]
Farming	enum	3	S-RATE5	both	Crop growth speed [5] [6]
FarmingSpeedNew	double	1.0	0.1–100	B42	Numeric growth-speed multiplier [5]
FarmingAmountNew	double	1.0	0.1–10	B42	Numeric harvest-yield multiplier [5]
PlantResilience	enum	3	Very High (1), High (2), Normal (3), Low (4), Very Low (5)	both	Water loss and disease resistance; 42.20 codes run high-to-low [5] [6]
PlantAbundance	enum	3	S-ABUND5	both	Harvest size [5] [6]
NatureAbundance	enum	3	S-ABUND5	both	Foraging (and on B41, fishing) richness [5] [6] [7]
FishAbundance	enum	2	S-ABUND5	B42	Fish stocks split out from nature abundance [5]
CompostTime	enum	2	1 wk (1), 2 wk (2), 3 wk (3), 4 wk (4), 6 wk (5), 8 wk (6), 10 wk (7), 12 wk (8)	both	Composter decay time [5] [7]
KillInsideCrops	boolean	true	true/false	B42	Indoor crops and herbs die; houseplants exempt [5]
PlantGrowingSeasons	boolean	true	true/false	B42	Seasonal growth rules [5]
PlaceDirtAboveground	boolean	false	true/false	B42	Above-ground farming; in-file warning: performance risk [5]
ClayLakeChance	double	0.05	0–1	B42	Clay-floor conversion odds at lakes [5]
ClayRiverChance	double	0.05	0–1	B42	Clay-floor conversion odds at rivers [5]

Vehicles

Key	Type	Default	Range / coded values	Build	Notes
EnableVehicles	boolean	true	true/false	B42	Vehicle spawning master switch; B41 UI equivalent exists [5] [7]
CarSpawnRate	enum	3	codes 1–5, none to high: None, Very Low, Low, Normal, High	B42	The B41 UI shows a three-step scale [5] [7]
VehicleEasyUse	boolean	false	true/false	B42	Unlocked, fuelled, keyless cars [5] [7]
InitialGas	enum	2	Very Low (1), Low (2), Normal (3), High (4), Very High (5), Full (6)	B42	Tank level in found cars [5] [7]
ChanceHasGas	enum	2	Low (1), Normal (2), High (3)	B42	Odds a found car has fuel at all [5] [7]
FuelStationGasInfinite	boolean	false	true/false	B42	Bottomless pumps [5]
FuelStationGasMin	double	0.0	0–1	B42	Pump fill floor; with max and empty-chance, replaces the B41 station-amount enum [5] [7]
FuelStationGasMax	double	0.8	0–1	B42	Pump fill ceiling [5]
FuelStationGasEmptyChance	integer	20	0–100	B42	Percent of pumps that start dry [5]
CarGasConsumption	double	1.0	0–100	B42	Fuel-burn multiplier [5] [7]
LockedCar	enum	4	S-FREQ6	B42	Locked-door frequency [5] [7]
CarGeneralCondition	enum	3	S-LEVEL5	B42	Spawn condition [5] [7]
CarDamageOnImpact	enum	3	S-LEVEL5	B42	Crash damage to the car [5] [7]
DamageToPlayerFromHitByACar	enum	1	None (1), Low (2), Normal (3), High (4), Very High (5)	B42	Pedestrian-strike damage [5] [7]
PlayerDamageFromCrash	boolean	true	true/false	B42	Occupant crash injuries [5] [7]
TrafficJam	boolean	true	true/false	B42	Wreck congestion on main roads [5] [7]
CarAlarm	enum	3	S-FREQ6	B42	Active-alarm frequency [5] [7]
SirenShutoffHours	double	0.0	0–168	B42	Alarm-siren duration; 0 runs until the battery dies [5] [7]
SirenEffectsZombies	boolean	true	true/false	B42	Sirens draw zombies [5]
RecentlySurvivorVehicles	enum	2	None (1), Low (2), Normal (3), High (4)	B42	Maintained "survivor cars" [5] [7]
ZombieAttractionMultiplier	double	1.0	0–100	B42	Engine-noise attraction scaling [5] [7]

The B41 sandbox UI documents the same vehicle option family (enable, easy use, spawn rate, gas, locks, condition, alarms, sirens, crash damage) [7], but the archived B41 SandboxVars listing does not include vehicle keys, so no B41 Lua names are pinned here [6].

Build 42 families: animals, wildlife, basements, map, firearms

Basements are confirmed sandbox-controlled on B42: random basement generation has its own nested table with a single frequency key [5].

Key	Type	Default	Range / coded values	Build	Notes
Basement.SpawnFrequency	enum	4	S-STORY7	B42	Random basement generation frequency [5]
Map.AllowMiniMap	boolean	false	true/false	B42	Mini-map window [5]
Map.AllowWorldMap	boolean	true	true/false	B42	World-map access [5]
Map.MapAllKnown	boolean	false	true/false	B42	Full map revealed at start; an MP rejoin bug against this option was fixed in 42.19 [2] [5]
Map.MapNeedsLight	boolean	true	true/false	B42	Reading maps requires light [5]
AnimalStatsModifier	enum	4	S-ANIM6	B42	Animal needs drain rate [5]
AnimalMetaStatsModifier	enum	4	S-ANIM6	B42	Same, for off-screen animals [5]
AnimalPregnancyTime	enum	4	S-ANIM6	B42	Gestation length [5]
AnimalAgeModifier	enum	4	S-ANIM6	B42	Aging speed [5]
AnimalMilkIncModifier	enum	4	S-ANIM6	B42	Milk accumulation rate [5]
AnimalWoolIncModifier	enum	4	S-ANIM6	B42	Wool growth rate [5]
AnimalEggHatch	enum	4	S-ANIM6	B42	Egg incubation speed [5]
AnimalRanchChance	enum	5	S-STORY7-style with Always (7)	B42	Animals found at farms [5]
AnimalGrassRegrowTime	integer	240	1–9999	B42	Hours for grazed/cut grass to return [5]
AnimalMetaPredator	boolean	false	true/false	B42	Off-screen fox raids on open hutches [5]
AnimalMatingSeason	boolean	true	true/false	B42	Restricts breeding to season [5]
AnimalSoundAttractZombies	boolean	true	true/false	B42	Animal calls pull zombies [5]
AnimalTrackChance	enum	4	S-FREQ6	B42	Track generation for hunting [5]
AnimalPathChance	enum	4	S-FREQ6	B42	Huntable animal paths [5]
MaximumRatIndex	integer	25	0–50	B42	Peak vermin infestation level [5]
DaysUntilMaximumRatIndex	integer	90	0–365	B42	Ramp time to peak vermin [5]
FirearmUseDamageChance	enum	2	Disabled (1), Zombies Only (2), All Targets (3)	B42	Chance-to-damage aiming model [5]
FirearmNoiseMultiplier	double	1.0	0.2–2	B42	Gunshot audibility to zombies [5]
FirearmJamMultiplier	double	1.0	0–10	B42	Jam odds; 0 disables jams [5]
FirearmMoodleMultiplier	double	1.0	0–10	B42	Moodle penalty on hit chance [5]
FirearmWeatherMultiplier	double	1.0	0–10	B42	Weather penalty on hit chance [5]
FirearmHeadGearEffect	boolean	true	true/false	B42	Headgear (masks) affect aim [5]

Applying changes: what is actually documented

The documented workflow is: edit the file (or use the in-client Host settings editor saving under the server's name), start the server, and confirm with showoptions or by reading the files back [9]. The only documented while-running path is for the .ini: save, then run reloadoptions [9]. No equivalent live-reload is documented for servertest_SandboxVars.lua [9]. The widely repeated blanket rule that every config edit requires a full stop — and its justification that the server rewrites files at shutdown — is a contested community claim, quarantined as Claim 4 of admins-foundation; this document takes no position beyond what is cited here.

B41 vs B42 Delta

Area	Build 41.78 (B41)	Build 42.20 (B42)
Schema	VERSION = 4, flat keys plus ZombieLore/ZombieConfig [6]	VERSION = 6; adds Map, Basement, MultiplierConfig tables and roughly triples the key count [5]
Population scale	Normal = 1.0, Insane = 4.0 on PopulationMultiplier [6] [7]	Renumbered: Normal = 0.65, Insane = 2.5, plus a Very High step [5]
Respawn defaults	Respawn on by default: 72 h cycle, 16 h unseen, 0.1 fraction [6] [7]	Generated file disables respawn (ZombieRespawn None; hours/fraction zeroed); migration stays on at 12 h [5]
Loot rarity	Enum steps per category (FoodLoot etc.); LootRespawn enum; respawn modifiers in server.ini [6] [7]	Numeric multipliers 0–4 across ~21 categories, six tier-factor keys, roll multiplier, removal lists, density-scaled loot, and a world "already looted / diminishing loot" model; respawn keys moved into SandboxVars [5]
XP	Single XpMultiplier (0.001–1000) [6] [7]	MultiplierConfig: global value + toggle + ~35 per-skill keys under internal names; media/dismantle XP cutoffs added [5]
Zombie lore	Includes Smell and Decomp; fixed-value defaults; TriggerHouseAlarm documented off [6] [7]	Drops Smell/Decomp; adds sprinter/door percentages, stealth logic, zombie armor, fence-damage tuning, fake-dead and spawn-clearing controls; randomized speed/toughness/sense defaults; TriggerHouseAlarm on in the generated file [5]
Utilities	Water/electric windows with day modifiers [6]	Adds AlarmDecay pair; electric windows floored at day 14; both gain a Disabled code [5]
World clock	Nine-step day length per the archived comment [6]	27-step day length defaulting 1 h 30; day/night, climate and fog cycle overrides; night length control [5]
Farming & nature	Enum speeds and abundances [6]	Adds numeric speed/yield multipliers, seasons, indoor-crop kill, clay chances, split fish abundance [5]
Vehicles	UI options documented; no Lua keys in the archived listing [6] [7]	Full key family pinned, including numeric pump-fill trio replacing the station-amount enum, and siren attraction [5] [7]
New families	—	Animals/wildlife (16 keys), vermin index, basements, in-game map table, firearm handling family, muscle strain/discomfort/wound factors [5]
Migrated from server.ini	MinutesPerPage, HoursForLootRespawn, MaxItemsForLootRespawn, ConstructionPreventsLootRespawn lived in the .ini [6]	All are SandboxVars keys at 42.20 [5]; corpse-removal hours likewise moved per the B41 UI docs [7]

The short version: keep the two builds' files apart. A B41 SandboxVars pasted onto a B42 server carries wrong-scale population numbers, missing keys and stale enum meanings; the safe path is to regenerate on the target build and re-apply intent, not text [5] [6].

Practical Guidance

• Generate, then edit. Let the server write its default file once, copy it, and change values from there — you inherit the correct VERSION, key set and per-build defaults instead of assembling a file from guides.
• Decide respawn explicitly on B42. The generated defaults mean a cleared block stays cleared. If you want B41-style pressure, set ZombieRespawn off None and give RespawnHours / RespawnUnseenHours / RespawnMultiplier real values — the B41 defaults (72 / 16 / 0.1) are a documented starting point.
• Translate, don't copy, population numbers. Convert B41 intent through the preset anchors: B41 1.0 (Normal) maps to B42 0.65; B41 4.0 (Insane) maps to B42 2.5. Setting PopulationMultiplier = 1.0 on B42 is between Normal and High, not Normal.
• Use internal names in MultiplierConfig. The keys are Woodwork, Doctor, PlantScavenging, Husbandry, Blacksmith, Lightfoot, Sneak, Blunt, SmallBlade — not the UI names. And remember GlobalToggle: while it is true, per-skill values are overridden by Global.
• Respect the in-file warnings. RollsMultiplier, PlaceDirtAboveground and ZombieConfig.ZombiesCountBeforeDelete all carry explicit do-not-change or performance warnings in the generated file; treat them as support boundaries, not tuning knobs.
• Treat SandboxVars edits as restart-required. Only the .ini has a documented live-reload path. Whatever the truth of the contested shutdown-overwrite claim (admins-foundation, Claim 4), stop-edit-start is never wrong.
• Verify after boot, not after save. showoptions against the running server is the ground truth for what actually loaded; a typo in Lua can silently fall back.
• Quote strings, comma-separate lists. LootItemRemovalList and WorldItemRemovalList take comma-separated full item types (Base.Hat style) as Lua strings.

Common Pitfalls & Troubleshooting

• A per-skill XP value "does nothing". Check MultiplierConfig.GlobalToggle — while true, Global wins [5]. Then check the key name: Carpentry, Foraging and First Aid are not keys; Woodwork, PlantScavenging and Doctor are [5].
• B41 guide keys silently ignored on B42. XpMultiplier, FoodLoot, WeaponLoot, OtherLoot, LootRespawn, ZombieLore.Smell and ZombieLore.Decomp are not in the 42.20 listing [5] [6]. The B42 replacements are MultiplierConfig, the *LootNew multipliers, and the loot-respawn hour keys.
• "Zombies never come back" on a fresh B42 server. That is the generated default, not a bug — respawn is zeroed [5].
• Loot rarity edited but numbers feel unchanged. On B42 the per-category multipliers interact with the world loot state — MaximumLooted, DaysUntilMaximumDiminishedLoot and friends can pre-loot or withhold loot independently of category rarity [5].
• Population feels wrong after migrating from B41. Re-read the multiplier mapping; the same number means a different world on each build [5] [6] [7].
• An edit made while the server ran has vanished. Only the .ini documents a live path [9]; see the quarantined shutdown-overwrite discussion in admins-foundation (Claim 4) before blaming the game or yourself.
• Mid-save edits appear to half-apply. See Claim 1 below — which keys apply retroactively to an existing world is not documented; test on a copy before promising rule changes to players.
• Sprinter shares don't apply. ZombieLore.SprinterPercentage is documented as taking effect when Speed is Random (4), not alongside a fixed speed [5].

Community Notes & Unverified Claims

Claim 1 — Some SandboxVars edits do not apply retroactively to an existing world

• Claim: Community guidance (hosting KBs, Reddit and Steam-forum threads) widely holds that certain sandbox values — variously named: loot already spawned, erosion progress, water/electricity countdowns, zombie population state — are baked into an existing save, so editing the file mid-campaign only affects newly generated chunks or has no effect, and only a fresh world honours every key.
• Why unverified: No primary source enumerates which keys are read live, which at world creation, and which persist in the save; the wiki documents the file and its defaults but not retroactivity semantics [5] [9].
• Confidence: Medium. The direction is plausible (world state such as spawned loot and utility-shutoff dates must live in the save) and the claim is consistent across many independent community sources, but the per-key boundary is unknown and some counterexamples (values that clearly do apply mid-save) circulate too.

Claim 2 — Hand-editing population multipliers above the documented maximum works

• Claim: Server-admin threads state that values beyond the documented cap — e.g. ZombieConfig.PopulationMultiplier above 4.0 — can be written directly into the Lua and are honoured by the server, enabling "beyond Insane" populations.
• Why unverified: The pinned listings document 4.0 as the maximum on both builds [5] [6]; no primary source describes out-of-range handling (accept, clamp, or reset) for hand-edited values.
• Confidence: Low. Reports are anecdotal, build-version rarely stated, and the behaviour could change with any hotfix; the documented range is the only safe contract.

Risks & Caveats

• The B41 evidence is the weak leg. The archived listing's SandboxVars block is stamped VERSION = 4 and its enum comments disagree with the B41 sandbox-UI docs in places (five- vs six-step population counts, six- vs seven-step mortality) [6] [7]. B41 key names cited here are solid; B41 enum numbering and defaults should be treated as approximate.
• Defaults quoted are generated-file values, not universal truths. The 42.20 defaults come from one wiki revision's rendering of the generated file [5]; a hotfix can move any of them. The 42.20.1-42.21 notes name no changed sandbox default [10] [11] [12], but they are behaviour notes rather than a schema diff, and no 42.21 server was inspected.
• UI-documented but key-unpinned options. For a number of B41 rules (vehicles, night darkness, poisoning, multi-hit) only the UI option is documented [7]; the B41 Lua key names are asserted nowhere in the cited record and are deliberately not tabled.
• Retroactivity is undocumented. Nothing cited here says which keys affect an existing world (Claim 1); every mid-campaign change is an experiment.
• Steam announcement URLs bot-block link checkers (verified via the ISteamNews API mirror per project source policy); pzwiki citations are revision-pinned and fact-only per the license rules.

Verification Steps

1. Regenerate and diff: on a scratch install of the target build, delete (after backup) servertest_SandboxVars.lua, start the server once, and compare the generated file against the tables above — key names, nesting and defaults.
2. Confirm the B42 listing: open https://pzwiki.net/w/index.php?title=Server_settings&oldid=1443167 and check the SandboxVars section against this document.
3. Confirm the B41 listing: open https://pzwiki.net/w/index.php?title=Server_settings&oldid=1393223 and check the VERSION = 4 block.
4. Confirm live values: run showoptions as admin against a running server and match a handful of edited keys.
5. Check a key from Lua: in a debug/console context, getSandboxOptions():getOptionByName("ZombieLore.Speed"):getValue() returns the live value by dotted name [8].
6. Corroborate patch-note keys: query https://api.steampowered.com/ISteamNews/GetNewsForApp/v2/?appid=108600&count=25&maxlength=0 and find the 42.20 note raising the zombie-deletion cap to 5000 and the 42.17 note naming Water/ElecShutModifier.
7. Probe Claim 1: copy a live save, change one key per area (loot multiplier, respawn hours, water shutoff), restart, and record which changes manifest.
8. Probe Claim 2: on a throwaway world, set PopulationMultiplier to 5.0, boot, and read the value back via showoptions to see whether it is accepted, clamped or reset.

Open Questions

• Which SandboxVars keys are world-creation-only versus live-per-session (Claim 1)? A developer statement or systematic save-diff testing would resolve it.
• What is the precedence between the windowed enums and their day modifiers (WaterShut vs WaterShutModifier) at 42.20? The archived B41 comment implies the modifier is the concrete day count [6]; the B42 listing documents both without stating the interaction [5].
• Does the B42 server clamp out-of-range hand-edited values (Claim 2)?
• Where is the B41 XpMultiplierAffectsPassive-style key actually named, if it exists — game files would pin what the wiki record does not [6] [7].
• Does 42.21 change any generated default or range? The patch notes name none [10] [11] [12]; a 42.21 server install would answer it.
• Will post-release B42 patching move the generated defaults (respawn zeroed, randomized lore) toward the B41 posture, or is this the intended stable baseline [1]?

References

Primary Sources

• [1] The Indie Stone — Build 42.20.0 Stable Released (Steam announcement, 2026-07-29; retrieved via Steam news API, ISteamNews app 108600). https://steamcommunity.com/games/108600/announcements/detail/1839676055882259. Accessed 2026-07-30.
• [2] The Indie Stone — Build 42.19.0 Unstable Released (Steam announcement, 2026-06-01; sandbox-option fixes incl. map-known and tainted-water tooltip). https://steamcommunity.com/games/108600/announcements/detail/1833968530897275. Accessed 2026-07-30.
• [3] The Indie Stone — Build 42.17.0 Unstable Released (Steam announcement, 2026-04-20; names Water/ElecShutModifier and the crawl-under-vehicle sandbox setting). https://steamcommunity.com/games/108600/announcements/detail/1830163047266254. Accessed 2026-07-30.
• [4] The Indie Stone — B42 CHECKLIST (Steam announcement, 2026-07-28; legacy41 branch instructions). https://steamcommunity.com/games/108600/announcements/detail/1839041357038237. Accessed 2026-07-30.
• [10] The Indie Stone — Re-population of the Dead: Build 42.21 Unstable Released (Steam announcement, 2026-09-23). https://steamcommunity.com/games/108600/announcements/detail/1844751498218925. Accessed 2026-10-07.
• [11] The Indie Stone — Build 42.21 Stable Released (Steam announcement, 2026-09-28). https://steamcommunity.com/games/108600/announcements/detail/1844751498231307. Accessed 2026-10-07.
• [12] The Indie Stone — 42.21 Patch Notes (TIS forum topic 101693, first post 2026-09-23; abridged copy). https://theindiestone.com/forums/topic/101693-4221-patch-notes/. Accessed 2026-10-07.

Fact-Only Sources (no prose reuse) — pzwiki (CC BY-NC-SA 3.0): cite URL + revision id; facts only, never prose.

• [5] PZwiki — Server settings (revision 1443167; page versioned against 42.20.0; full SandboxVars listing). https://pzwiki.net/w/index.php?title=Server_settings&oldid=1443167. Accessed 2026-07-30. Fact-only source.
• [6] PZwiki — Server settings, archived Build 41 revision (revision 1393223, 2026-05-23; SandboxVars block stamped VERSION 4). https://pzwiki.net/w/index.php?title=Server_settings&oldid=1393223. Accessed 2026-07-30. Fact-only source.
• [7] PZwiki — Custom Sandbox (revision 1442995; page versioned against 41.78.19; sandbox-UI option documentation). https://pzwiki.net/w/index.php?title=Custom_Sandbox&oldid=1442995. Accessed 2026-07-30. Fact-only source.
• [8] PZwiki — Sandbox options (revision 1442317; page versioned against 42.19.0; mod-defined options and Lua access). https://pzwiki.net/w/index.php?title=Sandbox_options&oldid=1442317. Accessed 2026-07-30. Fact-only source.
• [9] PZwiki — Dedicated server (revision 1443349; page versioned against 42.20.0; file locations, generation, showoptions/reloadoptions). https://pzwiki.net/w/index.php?title=Dedicated_server&oldid=1443349. Accessed 2026-07-30. Fact-only source.

Further Reading

Further Reading

• The Steam news API mirror used to verify the primary announcements: https://api.steampowered.com/ISteamNews/GetNewsForApp/v2/?appid=108600&count=25&maxlength=0
• Albion's community Sandbox Options modding guide (linked from the wiki modding page): https://github.com/demiurgeQuantified/PZModdingGuides/blob/main/guides/SandboxOptions.md
• The official blog / Thursdoid feed (bot-blocks automated checkers; read in-browser): https://projectzomboid.com/blog/

Related Documents

• admins-foundation — the Admins-track overview this document deepens; carries the quarantined config-editing-workflow claim (its Claim 4) referenced here.
• admins-server-ini-reference — the companion per-key reference for servertest.ini.
• players-foundation — the player-facing view of the B41/B42 split these settings run on.
• meta-style-guide — the style rules this document conforms to.

Revision History

Version	Date	Author	Change	Approved By
0.1.0	2026-07-30	KB Pipeline (virtual agent)	Initial draft.	—
0.2.0	2026-10-07	KB Pipeline (revision worker)	Re-baselined to 42.21: reviewed the 42.21 unstable and stable Steam notes [10] [11] and the TIS forum changelist [12]; added zombie-fix note, scope statement, removed stale 'days old' caveat. Key schema not re-extracted.	—
1.0.0	2026-10-08	Orchestrator (KB Pipeline)	Approved and frozen — release kb-release-2026.10.08 (42.21 re-baseline; validated against 42.21 and 41.78.21, Umbrella 42.21.0 @ 13d01f9). Content is the reviewed 0.2.0 text.	Project owner (user instruction 2026-10-08)