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Project Zomboid Build 42 Dedicated Server Setup

Project Zomboid Guide • Updated Jan 16, 2026

Project Zomboid Build 42 Dedicated Server Setup (Unstable)

Build 42 is the biggest Project Zomboid update in years, but it is still on the unstable branch. Use this guide to spin up a separate Build 42 server, keep your stable server intact, and avoid common multiplayer pitfalls.

Important: Build 41 and Build 42 saves are not compatible. Treat Build 42 as a separate test server until it reaches stable.

Planning Checklist

Task Reason
Clone a new server directory Keep Build 41 and Build 42 separated
Backup saves and configs Build 42 saves cannot downgrade
Review mods Many mods are not Build 42 ready
Match client branch All players must use the unstable branch

Step 1: Install Build 42 with SteamCMD

Use SteamCMD and the unstable branch. Example:

steamcmd +login anonymous +force_install_dir /opt/pz-b42 +app_update 380870 -beta unstable validate +quit

If you use a hosting panel, select the unstable branch for your server profile.

Step 2: Configure Server Settings

Server settings live in Zomboid/Server/ as servertest.ini (or your custom name). Common settings to adjust first:

ServerName=Build 42 Test
MaxPlayers=16
Public=false
Password=
PVP=false
WorkshopItems=
Mods=

Use a separate server name so players can clearly identify the Build 42 test environment.

Step 3: Review Mods Carefully

  • Disable non-essential mods until Build 42 compatibility is confirmed.
  • Keep WorkshopItems and Mods lists aligned.
  • Update mods before every server restart.

Step 4: Launch the Server

Use the standard start script for your platform, but point it to the Build 42 install and server name. Example (Linux):

./start-server.sh -servername "servertest"

On Windows, launch StartServer64.bat and select the same server name.

Step 5: Keep Clients Synced

Every player must opt into the unstable branch. If clients are on Build 41, they will get a version mismatch error when connecting.

Troubleshooting

Server starts but players cannot join

Confirm the server and clients are both on the unstable branch. Re-run SteamCMD updates if needed.

Mods cause startup crashes

Disable mods, start the server once, then re-enable mods one at a time.

Save file errors

Start a fresh Build 42 world. Build 41 saves will not load correctly.

Related Guides

Need a reliable test environment? Host your Project Zomboid server with Supercraft and swap branches in minutes.

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