Now that you mention it we did play with mods. It's been so long I forgot. Also, I'm not the expert here so I thought a delete and reinstall in steam would be a fresh clean install. Shows you what I know.

Thanks

Harmony X is a mod

You need to have a "clean" install.

To do this you need to..

Uninstall game

Go to folder manually in steam - steamapps - common - valheim and delete the entire folder

Reinstall game and check operation before you add in any mods.

The problem is an uninstall will not remove files the game did not put in, so you must manually delete the install folder to clear it out.