System.IO.IOException: The filename, directory name, or volume label syntax is incorrect.
An error occurred while attempting to auto-load your save file.
Should be enough information to indicate that one of your drives has a bad file. Try running the dev build to see what the error message says, it might help indicate what folder has the bad files.
https://projectpokemon.org/home/files/file/2445-pkhex-development-build/