By default, Offline Files is enabled on Windows 2000 Professional and Windows XP Professional, and disabled on Windows Server products.
To disable Offline Files, set the Allow or Disallow use of the Offline Files feature at Computer Configuration / Administrative Templates / Network / Offline Files to disabled. The setting disables the Enable Offline Files option on the Offline Files tab to prevent users from changing the setting.
I also use a Startup script to:
RD /S /Q %SystemRoot%\CSC
regsvr32 /s /u mobsync.dll