Error Code 16, corrupted saves

marciastalks​  You've say you've stopped OneDrive from touching the Sims 3 files, but have you moved your Documents directory out of OneDrive entirely?  That's often what's necessary to get around this issue.  How to do so is covered in the first post of this thread (for a related error), under the spoiler:

[Current Issue] Sims 3 "serious error" when loading save | EA Forums - 8322938