ladykyera999 If you need to keep OneDrive running in general, there are two options not covered in that guide that might work better for you. One is to simply create a new admin Windows account and play there. Make it local, as in, not tied to your Microsoft account or any email address (you can keep declining until you get some security questions instead), and it won't hook into OneDrive. But your main account will still have its current setup. You'd just need to switch accounts when you wanted to play, or at least when you wanted to play in live mode rather than building or creating sims.
The other option is to use the registry edit in the guide I linked to move Documents out of OneDrive, while leaving OneDrive running and syncing your files overall. The key here is that OneDrive only syncs data within its designated folders. Sims 3 uses your Documents directory, wherever that is. So that directory could be here:
C:\Users\your username\Documents
while OneDrive is still syncing whatever you put here:
C:\Users\your username\OneDrive\Documents
You would of course need to manually move or copy any files you wanted to sync, but that might not be a problem if it's an infrequent occurrence.