How to Disable / Restrict Use of USB Storage Devices in Windows?

Many times we want to restrict users from using USB drives in our systems. Suppose you have some important data and a friend comes and takes the data in his USB drive. This tutorial will help you in completely disable the use of USB drives in system.
After applying this tutorial, users will not be able to use USB drives. Windows will not detect it.
The tutorial is divided into 2 parts:

• If the USB storage device is not installed in system
• If the USB storage device is already installed in system

So lets start this tutorial:

If the USB storage device is not installed in system:

1. Type %windir%\inf in Explorer addressbar or RUN dialog box and press Enter. It'll open "inf" folder.
2. Now look for following 2 files:

• usbstor.inf
• usbstor.pnf

3. Now you have to change their user permissions setting. Do as following for each file:
Right-click on the file and select "Properties". Goto "Security" tab and select the desired user or group in "Group or user names" list which you want to restrict from using USB drives. Now in "Permissions for Users" list, click on "Deny" checkbox next to "Full control" option and then click on OK.

NOTE: In Windows Vista, you'll have to click on "Edit" button after selecting the user or group in "Group or user names" list and then again select the same user or group in new dialog box. Now you can click on "Deny" checkbox.
4. That's it. Now users will not be able to install any USB storage device in system.

If the USB storage device is already installed in system:

1. Open regedit and goto:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\UsbStor

2. In right-side pane, change value of "Start" to 4

3. Now whenever a user will attach a USB storage device which is already installed in system, Windows will not detect it and it'll not be shown in My Computer.
NOTE: If you want to revert it back to default, then change the value of "Start" to 3