Onedrive for Business Does Not Sync (Repairs Do Not Work)
Sometimes Onedrive for Business will enter a state where syncing will fail and all attempts at repair will not work.
The only solution is to clear the Onedrive for Business cache, and re-sync all your document libraries.
To clear your cache, close all your Office applications and processes such as groove.exe (which is Onedrive for Business), msouc.exe and msosync.exe.
Before you perform the next step, move all the locally cached document libraries, saved in the SharePoint folder to a temporary location (such as Desktop). This will ensure you keep a copy of the latest changes that have not synchronised to the server. You may delete these folders after you have confirmed the re-synchronised libraries have the latest documents.
Browse to “C:\Users\%username%\AppData\Local\Microsoft\Office\Spw” (where %username% is your current logged in username) and delete all the files and folders.
Next, go to “C:\Users\%username%\AppData\Local\Microsoft\Office\15.0\OfficeFileCache” (where %username% is your current logged in username) and delete all the files and folders.
After you deleted everything, start Onedrive for Business, login to your SharePoint Online site and re-sync all your document libraries (one at a time).