How to block and prevent external USB flash drives from being used on Windows 10

 When loaning your computer , it's always a good idea to be careful with everything that can be put into it. For example, a common source of viruses and unwanted files may come from external USB drives or hard drives, which easily can be connected to your computer .

If you are on a network, Windows has some policies that block such devices, but if you are using the computer outside of a network, there is a simpler trick to block any USB flash drives / Hard drive .

To perform this task, you will need to change in the system registry. Therefore, it is recommended to create a restore point or make a copy of your important files before proceeding . Moreover, it must be said that the procedure can be easily reversed in case you want to restore it to its previous state, as shown below.

NOW How to block external USB flash drives in Windows on your computer

To perform this task, in addition to other in-depth system modifications, you must have an account with administrator privileges. Check how to proceed:

Press "Win + R" keys together to open the "Run" window and enter the command: regedit then Press "Enter";

From the menu on the left side of the screen, navigate to this path: HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Services \ UsbStor;

Double click on "Start"

Change the value to "4" and click "OK";

Restart your computer. After restarting , when you connect an external USB device, you will not be able to access it through File Explorer in Windows. 

PS: such a change can also affect some smartphones, which sometimes identify themselves as an external storage device.

To reverse the task , all you need to do is re-access the same registry and change its value back to "3", and don't not delete the original registry under any circumstances as this will cause some serious problems within the system.