Hm... If running the game as admin doesent solve it for you, you could try doing this:
Go to your "AppData/LocalLow" folder and find the "Necro Bunny Studios" directory. Move it somewhere else and launch the game. It will recreate this directory. Now merge your old directory with the new one and ignore the redundant files when the explorer asks you about it. This should work and allow you to keep your saves.