The CSC (Client Side Caching) cache / database has built in recovery if it is suspected of being corrupt.
The Offline Files cache is a hidden folder structure at %SystemRoot%\CSC. Any direct modification of files is pretty much guaranteed to loose your data.
If you suspect corruption:
1. Use the Offline Files viewer to delete all the files.
2. Use Synchronization Manager to force synchronization.
3. If the cache is now functioning, exit this procedure.
4. Perform an Offline Files reset:
A. Select the Offline Files tab.
B. Press CTRL+SHIFT in Folder Options.
C. Press Delete Files.
D. You will receive:
The Offline Files cache on the local computer will be re-initialized.
Any changes that have not been synchronized with computers on the network will be lost.
Any files or folders made available offline will no longer be available offline.
A computer restart is required.
Do you wish to re-initialize the cache?
E. Press Yes and Yes to restart the computer.