I know this is marked as 'solved' but not sure it really is. I have used OneDrive to sync my QuickBooks Desktop between multiple computers for 3 years. I sync the entire folder that has the company file and all associated files and it works great...until yesterday. For some reason is stopped sync'ing. OneDrive support was no help. This thread was of very little help. 

I solved the issue by opening my OneDrive online account in a web browser. Then I dragged and dropped the latest QB files that were not sync'ing from my PC into the appropriate folder on the web browser.  Fixed the issue. Now QB is sync'ing as it always did.