disable users from connecting USB storage devices to their computers, here’s the trick:

Open registry and navigate to the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet \Services\UsbStor

Now in the right pane, double-click Start and type 4 in the Value data box (Hexadecimal) and quite the registry editor. To enable the USB storage devices, change the Start value back to 3.