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.