I started getting the message 'failed to Create the provider' while trying to sync my folders.
This is the fix, courtesy of 'Lior Messer' on Microsoft Forums:
Do a "Repair" for "Microsoft SQL Server Compact" and "Microsoft Sync Framework 2.0" ...
Original forum post here:
However, all I had to do was uninstall Synctoy and anything that mentioned "Microsoft Sync Framework" and reinstall, as I didn't have the Synctoy V2.0 media, just a new installer for 2.1.
and all is working fine for me again now....