Project Zomboid 42.21 Patch Notes — The Zombie Disappearing Fix, MP Duplication & XXL Tree Cutaways

Project Zomboid Build 42.21 is on the Unstable branch, and it contains arguably the most important multiplayer fix of the Build 42 cycle: zombies no longer disappear after a player leaves and re-enters a chunk of the world.

The Indie Stone describes that one as a tricky bug to pin down at its root, and it hurt hardest exactly where it mattered most — higher zombie population games and hardcore communities. Zombie duplication in MP has also been tackled, and the XXL trees that arrived with Build 42 Stable got a round of cutaway changes.

The full notes come from the developers — check out the complete 42.21 patch notes from The Indie Stone.

🎟️ Big Ticket Items

• Zombies no longer vanish after a player leaves and re-enters a chunk. Fixed in both single-player and multiplayer. This was the long-standing complaint from large-population servers, where a hardcore horde could quietly evaporate as players moved around the map.
• Zombie duplication in MP has been addressed — and The Indie Stone explicitly asks players to watch for any remaining instances once Unstable is live.
• XXL tree cutaway behaviour was reworked. Feedback since B42 Stable focused on the new XXL trees getting in the way, especially while driving. In 42.21 they cut away better for players in vehicles, no longer hide houses and furniture they overhang, and have adjusted transparency for better overall visibility. Bohemia — sorry, The Indie Stone — describes this as a work in progress and wants feedback; a developer reply in the thread confirms the trees will be modified further.
• loadstring and loadstream are re-enabled. They were disabled in the 42.20.4 Stable hotfix to address security vulnerabilities; after further investigation the team decided to re-enable them. They apologise directly to modders and server admins for the disruption.

✨ New

• Characters automatically re-equip items after exercise.
• The in-game player map was updated to remove inaccuracies while exploring.
• Localization system updated to enable more translatable strings.
• UI "Spawn Point Selection" preview videos updated to match the Map Glowup.
• A notification now appears when you try to connect to an MP server running a different game version.
• Improved player pathfinding to avoid trampling farming plants where possible. The notes clarify this is purely cosmetic — player characters do not damage crops by stepping on them.
• Updated in-game credits.

⚖️ Balance

• The Welder occupation now starts with Welding recipes instead of Blacksmithing recipes.
• 86 more fluid containers can now be used to purify water in the appropriate oven type.
• Washing machines now clean dirty rags, strips and bandages.
• Fridges and freezers now warm gradually on the day the power goes out — no more instant spoilage cliff.
• Refrigeration is applied correctly to food items inside a bag placed in a fridge or freezer.
• Antibiotics can be packaged using the "pack in box" crafting recipe.
• Subbiomes won't generate trees on dirt.
• Brightness increased on several lamp and illuminated tiles.
• Floorboard stash containers found via annotated maps are now more appropriately named.
• Explosives now work in basements.

🐞 Fixes — Single-Player & Multiplayer

• Fixed the zombie disappearing issue after leaving and re-entering a chunk (very visible in high-population games).
• Fixed several cases of zombie duplication in MP.

🛡️ Multiplayer — Anti-Cheat, Servers & Exploits

• Expanded the anti-cheat system, guarding against various new cheats and remedying safehouse exploits.
• Fixed an issue where players could enter dedicated servers without correctly authenticating via Steam, which had been preventing SteamID bans from working. A significant one for anyone running a public server.
• Fixed an additional duping exploit with bags, an exploit letting players remove corpses from padlocked containers, one allowing popcorn machines to be duplicated, and a Sandbag duplication issue when building sandbag walls.
• Fixed an exploit where players could rest on the ground while chopping a tree, and one letting players collect sand, dirt or gravel — or make chum — from inside a vehicle.
• Fixed an issue where players could interact with world objects while the player map was open.
• Fixed being able to briefly see inside locked crates by picking up adjacent corpses, and from a vehicle, drag corpses or put animals into your inventory.
• Fixed an issue allowing players to remove XXL trees instantly via the context menu's "Remove Bush" option.

🌐 Multiplayer — Browser, Connection & Latency

• Server Update now displays the last wipe, not the last restart.
• "Connect" is disabled when no server is selected, and Role ordering now places each new role at the bottom of the Role list UI.
• Fixed driving problems at high ping (~150+): the map not loading in front of the car, passenger teleportation, and general MP juddering should all be improved.
• Fixed an issue that could block clients from loading into a server, and fixed connecting to a dedicated or hosted server when the UsernameDisguises option is enabled.
• Fixed the "Safety Disconnect Delay" server option, and a conflict between Disable Safehouse When Owner Connected=true and Sledgehammer Online in Safehouse=true.
• Applied the packet rate limit only to unconnected addresses, and fixed the RakNet reliable data stream failing to scale throughput at ~150 ms ping.
• Fixed an issue where returning players could see previously unexplored areas of the map, and players being able to see the nickname of a hidden character.
• Fixed being able to confirm a Trade without the other player's confirmation.

🔄 Multiplayer — Sync, Desync & World State

• Fixed a Z-level desync for better player coordinate synchronisation, zombie coordinate desync, desync after a zombie knockdown event, desync around moments where player characters are falling, and synchronised players' appearance between chunks.
• Fixed dropped broken items not being lootable on the ground — with clothing condition now handled server-side.
• Fixed the action of turning off an alarm not saving on the gameplay UI screen and being heard again after loading a save, and notes made in your backpack not saving.
• Fixed changes in player perks not being written to PerkLog.txt.
• Fixed a sleeping character waking up when another player aims on the same chunk.
• Fixed a memory leak caused by eating food directly from a vehicle trunk, and an error caused by objects loading after packets have been sent.
• Fixed instances of animals not spawning on the map due to a server error, and a long delay between an animal's kill and its final death state.
• Fixed an issue which would allow players to enter dedicated servers incorrectly, additional server and client errors and crashes, and a client crash that could occur due to zombie environmental attacks.

🎮 Multiplayer — Characters, Actions & Animations

• Fixed characters getting stuck performing the spear thrust after teleportation, characters pausing when doing a 180, and character standing up while sitting on the ground fishing.
• Fixed stamina being infinite after interrupting a timed action while seated on furniture, and the "warming hands" animation not playing near a campfire.
• Fixed remote players showing the "open window" animation whenever they cancelled an action, a repeated animation after taking pills, and the firearm "Rack" animation not playing when walking.
• Fixed remote player models having poor pathfinding among furniture objects, and a car model blinking when a remote player swaps seats.
• Fixed walkie talkie VOIP not working while driving a vehicle, and headphones or earbuds not being interactable after removing them from a radio.
• Fixed zombies not staggering when attacked, and zombies not tearing down sheet ropes.
• Fixed an issue in the "throwing a zombie over the fence" animation looking poor or inaccurate for remote players, and an inconsistent spear animation in certain locations.
• Fixed animal deaths counting as player deaths in kill count totals, and Nimble XP not being granted in combat stance (MP only).
• Reduced Muscle Strain from digging a single grave, bringing it closer to single-player values.
• Fixed an error when reloading a butcher hook with an animal attached, butcher hook UIs overlapping, and being unable to butcher or mount dead animals found in trailers.

🧰 Multiplayer — Servers, Admin Tools & UI

• Fixed several admin teleport commands ("Player1", "Player2") and grantadmin/setaccesslevel Player Role when a user isn't on the whitelist.
• Fixed a player getting kicked from the server when trying to execute a server command, and being unable to launch a closed hosted server by ensuring the host's default role is admin.
• Fixed the missing ShowCoords setting in Host, and clicking Start multiple times while creating a hosted world spawning multiple server consoles.
• Fixed the brush tool for admins, and the debug context-menu "Kill" command not working on animals in trailers.
• Fixed the character name length limit in the "Add Player" UI — now a maximum of 32 characters.
• Fixed tooltips not showing items inside a bag, the Seasoning label not appearing on food tooltips for items without spices, map symbols sharing button being available when reading Map items, and x2/x4 scope attachment icons.
• Fixed the page-count progress bar stopping while reading a book, and not being able to read all pages in a skill book.
• Fixed not being able to see the book or magazine if read directly from a container for remote players, and the crossword magazine missing from a character's hands while reading.
• Fixed an issue where clicking Start more than once opened duplicate server consoles, and Discord integration causing an infinite connection loop when the Discord API is unavailable.

🏗️ World, Building & Objects

• Furrows trampled by zombies are now removed entirely from the game and world (with an error fixed when zombies walk over un-sowed furrows).
• Fixed being able to build a wall on top of stairs that blocks people in, and destroying a west-facing intersection wall taking out the north-facing wall instead.
• Fixed visible seams between 30-degree roof tiles across chunk boundaries, and a game crash when removing a player-built wall in an enclosed room.
• Fixed player-built campfires having collision with vehicles, and an error when removing a campfire with its info window open.
• Fixed a charcoal burning barrel not working after being picked up and placed, a moved composter throwing errors when interacted with, and Sandbag duplication when building sandbag walls.
• Fixed an issue that could cause the game to freeze indefinitely when generating looted buildings.
• Fixed the deprecated tankless SCBA breathing apparatus still spawning and appearing usable or lootable.
• Fixed an issue where some game assets (zombies, weapons, vehicles) failed to load and displayed only as shadows — plus BufferUnderflow errors when driving the RaceCar.
• Fixed an exception when dead bodies turned into skeletons, and WorldReuserThread mutating IsoObject/IsoGridSquare.

🖥️ UI, Visuals, Camps & Misc

• Fixed an instance where unlucky survivors could spawn inside the barricaded, locked gun shop in Rosewood.
• Fixed Road Stories not spawning correctly in some areas of the updated glow-up map, some boulders being cut off, and RiversideStashMap2.
• Fixed an error when finding floorboard stashes with foraging, and Lightbulb right-click context menu behaviour.
• Fixed the crafting UI not closing after removing a crafting station, and being unable to queue "Install" actions using the Mechanics skill.
• Fixed issues where spaces and percentages were not visible in the game UI, and Shift behaviour when using the Colour slider in character creation.
• Fixed an error when adding bait to a fishing rod, and an error when destroying TVs with a sledgehammer.
• Fixed a performance issue when Throwables become active on high buildings, and the 3D model size of 1L and 2L plastic bottles.
• Fixed the epilepsy warning loading screen not being centred on initial load, and an error when first loading on Steam Deck.
• Fixed ATMs placed in front of barricaded windows displaying behind the barricade, and the icon for braziers. Plus fixes for frying pans and garden fence gates being breakable during the tutorial, and the Tritium Pistol Sights tooltip.

🎮 Split Screen

• Fixed a crash when the local and co-op player are both in the same moving vehicle.
• Fixed split-screen controls for both players after a gamepad disconnects, and an incorrect account username when loading a Split Screen character.
• Fixed read book status and XP boosts being shared incorrectly between split-screen characters.
• Fixed fish bubbles disappearing after adding a second character, and Player 1 being unable to fish if Player 2 is too far away.

🔊 SFX & Technical

• Fixed the player not hearing the "vehicle ignition fail" SFX, specific fence pieces playing the wrong zombie thump sound, and SFX issues when cars hit traffic cones in MP.
• Added a Seam Editor to the Debug Menu.
• Reduced unnecessary console logging near map-placed farming plants, and improved MP logging for tech support.
• Added a "ToggleOldRenderer" keybinding, unset by default — this was previously the Home key toggle.

🖥️ What This Means For Your Server

• The chunk zombie fix is the headline for high-population servers. Zombies vanishing when a player left and re-entered a chunk made large horde settings unreliable — precisely the configuration hardcore communities run. If your server compensates with heavy zombie populations, this is the build to test.
• Zombie duplication and the bag/corpse/sandbag exploits all get addressed. Duplication in a survival economy is close to a fatal problem — it inflates loot, breaks progression and erodes trust in the world. Combined with the expanded anti-cheat and safehouse exploit remedies, this is a strong integrity update.
• The Steam authentication fix restores SteamID bans. Players who could join a dedicated server without properly authenticating were effectively ban-proof. Any server admin who has fought a persistent troublemaker will feel this one.
• loadstring/loadstream are back. If your server or mod collection depends on those commands, re-test them on 42.21 — they were disabled in the 42.20.4 hotfix for security reasons and have now been deliberately restored after investigation.
• High-ping driving and RakNet throughput improvements matter for hosting. Fixes aimed at ~150 ms ping show the team treating latency-related MP bugs as real; better throughput scaling at that latency means a more playable experience for players who aren't near your server region.
• Version-mismatch notification saves admin time. A clear message when a player connects with a different game build removes a whole class of confusing "I can't join" reports.
• Back up before testing on Unstable. The team's own advice: saves from 42.20.4 should be fine, but take a manual backup first, and only report bugs you can reproduce on a fresh save with no mods — that's what makes reports actionable on the Bug Reports forum.
• XXL trees are still in flux. The cutaway changes are explicitly a work in progress — expect further passes, and don't rebuild your server rules around their current behaviour.

Running a Project Zomboid community? NolimitHost Project Zomboid server hosting gives you the CPU headroom that large zombie populations and long-running worlds demand, alongside DDoS protection and automated backups — so testing an Unstable build never puts your live save at risk.

Conclusion

Build 42.21 is a substantial update even by Build 42 standards. The zombie disappearance after chunk re-entry is fixed in SP and MP — the bug that most damaged high-population hardcore servers — MP zombie duplication is tackled, XXL tree cutaways were reworked for drivers and visibility, and loadstring/loadstream are re-enabled for modders and server admins. Alongside that: a broad balance pass (86 new water-purification containers, washing machines cleaning bandages, fridges warming gradually when the power dies, Welder recipe correction, explosives working in basements), a large set of multiplayer integrity fixes (Steam auth, safehouse exploits, duplication, anti-cheat), serious desync and high-ping driving work, plus split-screen, SFX and tooling improvements including a new Seam Editor.

Read the complete, official write-up from The Indie Stone: 42.21 Patch Notes.