Troubleshooting Project Zomboid Build 42

Project Zomboid writes its logs to a Zomboid folder in your user profile, not to the Steam install folder. The same folder holds your saves and server settings. Close the game before you copy anything from it.

console.txt is overwritten every time the game starts, so copy it right after a crash. The game also writes logs.zip in the same folder, which is the file to attach to a bug report. Dedicated servers write dated files such as DebugLog-server.txt into Logs.

To read the log, reproduce the problem once, quit, and open console.txt in a plain text editor. Search for the first line containing ERROR, Exception, Caused by or stack traceback. The first error is usually the cause; the hundreds of lines after it are often knock-on noise. A mod folder name or Workshop ID near that first error points straight at the culprit.

Work through these in order and test after each step.

1. Update your graphics driver from NVIDIA, AMD or Intel directly. An EXCEPTION_ACCESS_VIOLATION in console.txt that names nvoglv64.dll or atig6pxx.dll points to the driver (one source).
2. Turn off the Steam overlay and other overlays (Discord, recording tools) for the game.
3. Verify game files in Steam (Properties, Installed Files). This does not touch your saves.
4. Start a new world with no mods. If that works, the problem is a mod or the save, not the install.
5. Make sure you launch the 64-bit client. Old 32-bit batch files are not a fix.

A black screen, often with menu sound, is usually a display setting the game cannot apply. Run in windowed or borderless mode at a fixed resolution and keep the game on your main monitor. One guide suggests deleting options.ini in the Zomboid folder to reset display settings (one source); rename it instead of deleting so you can put it back. On Windows, the high DPI override in the executable's Compatibility tab fixes a clipped interface. Check your build against patch notes, since some 42.21 black screen reports had no confirmed fix at the time of writing.

A Java heap or OutOfMemoryError line in console.txt means the game ran out of the memory it is allowed to use, not out of system RAM. Raise the limit only when the log shows this error, and update the game first.

Sources disagree on the stock value. pzfans lists -Xms1800m and -Xmx2048m on Windows and -Xmx3072m on macOS, while another guide shows -Xmx3072m in the Windows batch file. Open your own file and note what is there before you edit it.

Back up the file, change for example -Xmx2048m to -Xmx4096m, save, and launch from Steam. Raise it in steps of 1 to 2 GB, keep -Xms at or below -Xmx, and never set -Xmx above the RAM you actually have. Typing memory flags into Steam launch options does not change the client heap, according to two sources. Steam updates and file verification can restore the original file, so check it after each patch.

Opinion On a 16 GB machine, 4 GB is a sensible first try. Going much higher rarely helps and can make pauses longer.

Stutter in single player usually comes from graphics load, heavy mods or the game loading new map areas while you drive. Lower lighting quality, water, 3D corpses and VSync first, then retest on the same route so the comparison is fair. Temporarily disable large map, interface and texture mods. On laptops, plug in and use a high-performance power plan. Close browsers and other heavy background apps.

For a full list of settings and their cost, see the performance guide. If the stutter only appears in large hordes, the sandbox settings for zombie population are worth a look on a new world.

The red number in the corner of the screen counts Lua errors the game has caught. It is not an official error code. Open console.txt, find the first error and look for a mod path or Workshop ID.

• Disable the suspect mod for that save from the Load screen (More, then Mods) and test once.
• If you cannot tell which mod is at fault, disable half the list, test, and keep halving until one is left.
• Unsubscribing on the Workshop does not remove a mod from an existing save's mod list. Disable it on the save itself.
• Many mods built before a Build 42 patch break after it. The loadstring error seen after 42.20.4 was a sandbox change that 42.21 reversed, according to build42guide.

Loading a save without mods it was built with can damage it, so back up the save folder before testing. More on load order and compatibility is in the mods guide.

Controller not detected. Plug the pad in before you start the game. Go to Options, then Controller, tick your pad, and press Reload .config files if it is missing from the list. If a mod interferes after a patch, reset controller settings to defaults. The controller guide and Steam Deck page cover layouts.

Cannot join a server. Most connection errors are version or mod mismatches.

A VPN is not a reliable fix. Hosting details are on multiplayer and hosting a server.

If none of this helps, the debug mode page explains how to get more detail, and the FAQ collects shorter answers.