The common denominator for all reports that I've seen is that they happen on Windows 10 - Version 1607 (Anniversary Update).
When there is time to dick around old Windows 10 builds, I'll see if I can figure out why does it happen.


I performed a windows update last night, and saves are working ...

Thanks for the report. "Incorrect function" means the operating system denied/errored the request to delete the temporary file used to save the game. If you're getting that error everything I can find about it says your hard drive is at fault: either the filesystem is corrupt or the disk itself is ...