Valheim Server Won't Start? World Load Failed, Check Backups and Other Common Issues

These are the Valheim server problems that come up most often in our tickets, with the fix for each, and they apply to any Valheim dedicated server. Where the fix lives on our panel, I've said where. If you're still shopping, a hosted Valheim server with us comes with that panel.

Server stuck at booting

I've taken a look over the last few years of our support and these three are the most common issues:

1. Corrupted World

This happens a lot more than you think and typically when it's been uploaded. To check if your world is corrupted, open the server log (the Console tab, on our panel) and search for the following:

World load failed mid-file. Exiting without save. Check backups!

or

Exception while loading world (...) Unable to read beyond the end of the stream.

First, work out which kind of world you have. Open the worlds folder, config/valheim/worlds_local/ on the Files tab.

• If your world is a folder with your world's name on it, it's a Valheim 1.0 world. Skip to "If your world is a folder" below.
• If your world is a .db and .fwl pair with no folder of the same name, it hasn't been converted to the 1.0 format yet, and the steps straight below apply.

To fix a .db and .fwl world, do the following steps:

1. Ensure your server is stopped
2. Take a backup first (Create backup on the Backups tab), so if anything else goes wrong we have a copy!
3. Open worlds_local
4. Upload your '.db.old' file (Valheim keeps it next to the world, or you may have one on your PC)
5. Delete the '.db' file
6. Rename the '.db.old' file you just uploaded to '.db'
7. Start your server and check the logs to see if the message is still coming up!

Note: If you have played on that world before with mods, ensure the server now has the same mods installed if not, the server will not load your save.

If your world is a folder:

Don't use the .db.old trick above. On a world that's been converted to 1.0, the .db.old and .fwl.old files are the original world from before the conversion, so bringing them back puts you on the world as it was that day and throws away everything since. Iron Gate built the 1.0 save format to survive a failed write much better than the old one did, but if it does go wrong:

1. Stop the server
2. Take a backup so the current state is kept, broken or not
3. Restore a backup from before the problem on the Backups tab, or open a ticket and we'll restore one of Valheim's own _backup_auto- folders for you

The whole subject is covered in backing up and restoring a Valheim server.

2. Mods or plugins are crashing the server

If you do have mods/plugins installed on your server, then it could be one of those preventing the server from booting.

It could be either a recent game update or one of the mods' dependencies missing. Valheim 1.0 upgraded the game's Unity engine, so right now the most likely cause is a mod that hasn't had a 1.0 build yet.

If you disable all the mods on the server and can connect, then that is one sure way to know if it is mods causing the problem. You can then add the mods back in one by one to find out which one is the culprit! On our panel that's uninstall on the Installed list of the Mods tab, and Valheim mods after the 1.0 update walks through the whole recovery.

3. The server password is being rejected

This one catches people out because it looks like the server is stuck, when really it started, refused the password and quit straight away. Search the log for:

Error bad password:

Two things cause it. The password has to be at least 5 characters, and it cannot appear anywhere inside your world name or your seed. So a world called Vikings with the password Viking will never boot, because the world name contains the password.

Change the password (or rename the world) in the General group on the Manage tab and start it back up.

Unable to connect?

We've made a guide/steps to help you connect to the server! Please feel free to read it here: https://low.ms/knowledgebase/valheim-cant-connect-to-server

Incompatible version

I do cover this a little in the guide I've mentioned above, however if you do get this message then it is more than likely your client or server needs an update!

Since Valheim 1.0 this comes up a lot. 1.0 launched on 9 September 2026 as version 1.0.7, and the 1.0.12 hotfix followed on 11 September, so a server that hasn't been updated since launch week won't let updated players in.

The following steps can be found in the link above as well:

1. Open Steam.
2. Navigate to Valheim in your library.
3. Click Properties > Updates and ensure automatic updates are enabled.
4. Update the server. A dedicated server doesn't update itself on a restart. On our panel the Game updates card on the Overview tab says one is waiting, and Update installs it.

One exception: Switch 2 didn't get the 1.0.12 hotfix, so Switch 2 players can't join a 1.0.12 server for now. The can't connect guide explains the workaround.

If there was an update for the server and you have mods installed please ensure you check the mods typically found on Thunderstore.io website and update these if they have been updated recently!