Project Zomboid Build 42.21: Disappearing Zombie Fix, XXL Trees and Patch Notes

Project Zomboid Build 42.21 is now live on the Stable branch. The Indie Stone released it to everyone on 28 September 2026, after a few days of testing on the Unstable branch. Nicknamed "Re-population of the Dead", it's the first incremental update since Build 42 went Stable, and its headline fix stops zombies from disappearing when you leave an area and come back.

Project Zomboid Build 42.21 at a glance

What does Project Zomboid Build 42.21 fix?

The Indie Stone calls these the big-ticket items in Build 42.21:

• Disappearing zombies: zombies could vanish after a player left a "chunk" of the map and came back. This was most obvious in high-population games, so it hit hardcore players hardest. It's now fixed in both single player and multiplayer.
• Zombie duplication in multiplayer: the worst cases have been fixed. The developers say a few instances remain on their radar for the next update.
• XXL trees: the large trees added in Build 42 now cut away better when you're in a vehicle, no longer hide the houses and furniture they overhang, and are more transparent overall.
• Modding commands: the "loadstring" and "loadstream" Lua methods, disabled in 42.20.4 for security reasons, are back on.

Project Zomboid Build 42.21 balance and quality-of-life changes

• Characters re-equip items automatically after exercising.
• The Welder occupation now starts with Welding recipes instead of Blacksmithing.
• 86 more fluid containers can purify water in the right type of oven.
• Washing machines now clean dirty rags, strips and bandages.
• Fridges and freezers now warm up gradually on the day the power goes out, and food in bags inside them is properly refrigerated.
• Explosives now work in basements.
• Your character avoids trampling farm plants where possible, and the in-game map is more accurate.

What's changed for Project Zomboid multiplayer?

• Anti-cheat: more cheats are now guarded against, and safehouse exploits have been fixed.
• Steam authentication: a hole that let players join dedicated servers without proper Steam authentication, which got around SteamID bans, has been closed.
• Driving with high ping (around 150ms or more) is smoother, with fewer cases of the map not loading ahead of the car or passengers teleporting.
• The server browser now shows the last wipe rather than the last restart, and you're warned if you try to join a server running a different game version.
• Split-screen fixes, including a crash when two players shared a moving vehicle.

How do Project Zomboid updates work now?

From Build 42.21 onwards, The Indie Stone says every update will go to the Unstable branch first for players to test, may get more changes, and then moves to Stable. The gap will depend on the update, but the team says it's trying to move faster, and Unstable shouldn't act as an unofficial Stable. To join Unstable, right-click Project Zomboid in Steam, choose Properties, then Game Versions & Betas. Back up your saves first.

Watch the Project Zomboid Build 42 showcase

More zombie survival on iGame Magazine

• Project Zomboid Build 42 Stable is out – the huge update this builds on
• 7 Days to Die 3.0 Dead Hot Summer – another zombie survival update
• Last Harbor revealed by tinyBuild – a new zombie survival game to watch

Project Zomboid Build 42.21 FAQ