Disable Steam Cloud on any account used on that PC. The saves are saved in appdata per Windows User not Steam User, so when you logged into your sons account Steam Cloud overwrote your data with his.
Steam Cloud is just terrible in general and notorious from losing sync and rolling back data on many many games, avoid using it unless absolutely necessary.

Originally posted by ddonnerdal:

Originally posted by Gunther Ultrabolt Novacrunch:

Did you access your steam account/Valheim from separate computers?

No, but I did log out from steam this morning and logged into my son's steam account. There I paid once again for Valheim (in his account) so that we could play online together on different computers later today.

Then I logout in to my original steam account again to continue with my character. It was then I discovered that I lost days and items.

PS. Have never exit a game with F4. I always use the main menu, the normal way.

Your new save data was overwritten by a copy of your save data that was uploaded to your son's cloud saves. This happened to me on a computer I share with my girlfriend, and I was lucky to have started backing up my saves the week before. I would have lost two or three weeks progress but instead all I lost was twenty minutes of figuring out the problem and restoring my saves.

Originally posted by Weaver:

Disable Steam Cloud on any account used on that PC. The saves are saved in appdata per Windows User not Steam User, so when you logged into your sons account Steam Cloud overwrote your data with his.
Steam Cloud is just terrible in general and notorious from losing sync and rolling back data on many many games, avoid using it unless absolutely necessary.

I've got hundreds of games and a living room computer I share with my girlfriend, and the only games I have ever experienced cloud save problems with were Death Stranding and Valheim. Death Stranding got fixed, here's hoping Valheim follows suit.

Did you access your steam account/Valheim from separate computers?j

Did you exit a game using alt f4?

Sounds like some sort of Steam Cloud crap.

Originally posted by Gunther Ultrabolt Novacrunch:

Did you access your steam account/Valheim from separate computers?

No, but I did log out from steam this morning and logged into my son's steam account. There I paid once again for Valheim (in his account) so that we could play online together on different computers later today.

Then I logout in to my original steam account again to continue with my character. It was then I discovered that I lost days and items.

PS. Have never exit a game with F4. I always use the main menu, the normal way.

As side note it is easy to "gift" a friend on your friends list instead of having to log onto thier account.

Definitely sounds like a steam cloud thing.

if I remember correctly if you disable it, it will ask you if you want to revert to a save on your disk next time you start up.

Also there is this: https://www.thegamer.com/valheim-world-destroyer-bug/

cut and pasted from devtrackers:

World save issues

Valheim saves both character and worlds in separate folders in:

C:\Users\


If you share computer (with different logins) with a family member, but you both share steam account. You can have issues with steam and cloud saves. Example:

Player 1 logins on computer, starts steam. (then steam cloud saves will sync files on launch) then when you exit the game, steam cloud saves will sync again) if then player 2 launches the game from the shared steam account, player 2’s local files will be prompted by steam if player 2 want to overwrite the files on c:

This can lead to issues if players 1 and 2 don’t always have steam connected and sync every time correctly. (like quickly close the computer for example so steam doesn’t get the time it needs to sync correctly)

On a dedicated server, if you don’t close the client correctly, you can get corrupted files.
Sometimes a save-file get corrupted. Go to your above mentioned directory. Your world will have files named with .old rename the files and remove the .old extensions and answer YES, when it prompts you if you want to overwrite a current file with the same name.
If your issue isn’t among these examples, please go to https://valheimbugs.featureupvote.com/ and look if someone else have posted about a save-issue that looks like it’s the same as yours. Or write a new ticket.
One easy solution to try is simply to stop steam cloud sync.

Thank you Gunther. I'm not very good with computers or with steam, so I'm still not sure how to fix this.

However I did go to your second link and found others that had the same issue.
It has to do with Steam cloud, creating problems when using 1 computer (only 1 windows account user) but 2 different steam accounts.

From what I can read the solution is as below. But I'm a bit scared to do this. Might I accidentely delete my character or restore the Character to the wrong date?

HERE IS THE SOLUTION THAT ANOTHER USER WITH SAME ISSUE POSTED:
"Looks like the solution was to both uncheck save to cloud for Valhiem for both profiles AND delete the current local cloud backups for both profiles in:
C:\Program Files\Steam\userdata\<SteamID>\<AppID>
By deleting the folders there and the remotecache.vdf file, it wont overwrite the files anymore.

<steamID> represents a string of numbers which represents each steam profile. You have to do this for each profile which plays Valhiem.
<AppID> represents the app id for the game, which for Valhiem is 892970."

Well... I'd hate to say "go for it" and have you lose everything. I'm just an average computer guy.

I'd ask around a bit more, make sure that solution makes sense... and if it turns out bad and you lose everything I've been looking for an excuse to start over and maybe we could start a play through together on a fresh seed.

I don't see how doing that would restore a world file which has already been overwritten. Sounds like it's only a solution to stop the same thing from happening again in the future.

I had a similar problem on another game..I think it was grim dawn

The cloud saves. I believe you also have a save on your hard disk.

My solution (disclaimer I'm not a pro) was to disable the cloud, and start the game up again, if i remember correctly (its been awhile) I got a prompt asking if I wanted to start the game from a saved file from MY PC and i said yes and all was good.

My problem came from logging in on my nieces computer while baby sitting her.

That might be right. The more recent save might still be located locally in Users\%UserName\AppData\LocalLow\IronGate\Valheim. I don't actually have much experience with Steam Cloud. If you're going to try it, back up everything in that directory somewhere else on your HDD first.

Thank you for your help. Since I do not want to take any more risks I will just learn from this mistake and in the future just copy all the files in C:\Users\donne\AppData\LocalLow\IronGate\Valheim to another folder. If I do that after every time I have played it should be easy to just restore the old data by replacing it with the files in my new folder, right?

Yep, that's how I backup my world file.

Did you shut down Steam or your computer right after logging out of the game? I've noticed that it can take up to 10 minutes for me to be able to play the game again so I'm thinking the save to the cloud must be fairly large so if you interrupt the transmission to Steam cloud you may lose stuff.