Prevent a USB key or hard drive from being connected to a computer

For security reasons, it can be a good idea to disable the use of USB peripheral devices like USB keys of external hard drives, which can be used to remove sensitive data that is stored a computer.

When you connect a USB key to a PC, Windows XP will detect it and install the necessary drivers automatically for this new peripheral. After that, each time that the key is connected to the computer, its detection will be automatic and transparent enabling ints access directly from the Windows Explorer or My Computer.

If you want to prevent the use of a USB device of this type on your computer, for security reasons, then it is possible to disable this automatic detection.

Note: This change must be performed while no USB devices are connected.

To do this, log onto the computer with an account that will allow you to perform this action and then click on “Start”, “Run” and type “regedit”. Click on OK and you will have the Windows Registry open in front of you.

Go to the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\USBSTOR

Next, double click on “Start” and indicate the hexadecimal value of “3” or “4” according to the action that you want to perform:

• The “3” activate the detection of USB peripheral devices.
• The “4” value disables the detection of USB devices.

Note: It is necessary to reboot your computer for these changes to take effect.

You can also download these two reg files which will take care of the changes for you.

To disable the detection of USB devices.

To re-activate the detection of USB devices

We also recommend that you read this tip that will allow you under Windows XP SP2 to prevent you from writing to removable USB devices, although you will still be able to read the data.