When you no longer need offline access to a network resource, open the sync item in Windows Explorer, right-click, and clear Always Available Offline. If the share involved is set for manual caching, Windows purges the items from your cache in addition to removing the offline access attribute. If the share is set for automatic caching, items that are currently in the temporary cache remain there. To delete those files, open the Offline Files option in Control Panel. On the Disk Usage tab, click Delete Temporary Files. Note, however, that this option does not affect files you have marked to be Always Available Offline.

To eliminate all items from the Offline Files cache so that you can start over, you'll need to make a small edit to the registry. Before taking this drastic step, make sure you synchronize all sync items that contain changes you made that haven't yet been copied to the server location. The following steps completely erase all files from your Offline Files cache:

1. Using an administrator's account, open Registry Editor (Regedit.exe) and navigate to HKLM\System\CurrentControlSet\Services\CSC\Parameters. (This key is not created until you use Offline Files for the first time.)
2. Right-click the Parameters key and click New, DWORD (32-Bit) Value.
3. For the name of the new value, type FormatDatabase. (Note there's no space in that name.)
4. Double-click the new DWORD value and assign it a value of 1.
5. Restart your computer.

After you restart and log on to your account again, you'll notice that there are no longer any sync items in the Offline Files section of Sync Center.