I used the launcher yesterday to update the game, then started a new character and played it without a hitch until this morning. When I came back to play again now the titular error message popped up despite the fact I didn't change anything since then.
However, Windows Update has downloaded and installed an update in the background and I didn't see the popup because I was playing so suddenly the computer restarted and the game probably didn't exit cleanly.
Is there some way to get it back on track?
EDIT: It also happens when I create a new character. I also tried deleting the whole game folder and nothing changed.
EDIT2: I deleted the Tome folder from documents and then just copied over unlocks and saves and it works
