JSI Tip 1116. Prevent a user from mapping a network drive.

If you set No Access permission, for a user, on %systemroot%\system32\mprui.dll, even OutLook users can't map a drive.

If you set No Access permission on NET1.EXE, you can further inhibit them.

If you set No Access permission on NET.EXE, they won't be abe to use the NET command (which means you can't map in a logon script).