As far as I know, It only affects players who kept their Saves (worlds) on the Steam Cloud. Steam had an update recently that had something to do with the Cloud and Cloud saves, and apparently it was no good for Valheim worlds/saves that were stored in it.

Don't worry, you are most likely to recover your world.

1. In game, move your corrupted save (World) from cloud to local. And I'd suggest keeping it that way.




While selecting a world, you can see some icons on the right. They indicate where you save is kept. 1 means it's in the cloud, and 2 means it's stored on your computer. Select the world in cloud (Do not start the game) and then just simply click "Move to local". Wait a few seconds and close the game.











2. Close the game and go to the Steam Cloud saves website.
Link: https://steamproxy.net/steamstore/account/remotestorageapp/?appid=892970

It is important to go there via web browser and not the Steam app.


Look for the most recent file of the corrupted save. In my case it would be "Midgard.db.old", as well as "Midgard.fwl.old". Download them on your computer and don't mind thre weird file names it downloads.

3. Rename the files. Remove everything from the file name, so the only thing that remains is "yourworld.db" and "yourworld.fwl" (Midgard.db/Midgard.fwl in my case).



4. Replace the Save files. Go to your Valheim saves folder (screenshot below), and simply put the renamed files in the folder. It should overwrite the already existing files.




After that, open up your game and join the world. It should work fine, but you may lose some progress as the cloud saves can date back to few months ago.

If that doesn't work, download the most recent backup files like these:

Then proceed to do the same operation; Rename the files so it's yourworld.db/yourworld.fwl and put them in the worlds_local folder.

Anyway, for now It's the best solution for this damn bug.