Can you locate your My Games folder. E.g.

C:\Users\[your username]\Documents\My Games\

If any of the text in this path uses symbols, or non-standard or non-western characters (e.g. é or ä, or Chinese/Korean/Japanese/Greek/Russian/Arabic) then this will cause this issue.

If so, please can you create a new Windows username that only features standard western characters and use this to play the game.