Invalid UTF-8 Encountered

[Roostay]

I've been playing this game with out issues in the last couple of days and have hit the above issue when trying to load up a game or even start a new one.
A quick search suggests mods are the issue, but I've not used installed any.

i'm not aware of an update having been installed.

Anyone else hitting this issue?
Thanks.

[Autocoach]

I would suggest getting steam to verify the integrity of the game files to see if that solves it.