When trying to use a hardware device attached to your computer, such as a USB optical mouse, your computer displays the error message for error code 20. Windows is having problems loading a device driver and is unable to use the affected device.
Resolving the Windows error code 21 is one of the easier problems you can solve. This error message usually pops up when someone has set a device to be removed and then selects the device again while in Device Manager. Windows makes the assumption that you are trying to access a device that is currently being removed and kicks up the error code 21 message, “Windows is removing this device.”
Here are some ways to deal with this pesky error message.
If you intended to remove the device, simply give the operating system a little more time to remove the device. Wait a few seconds and see if the Device Manager still shows the device as existing on the system. If the device is still showing up, don’t click on it or you will see the error message again. Instead, hit the F5 key to refresh your Device Manager screen. You should see the device going away soon.
If waiting doesn’t get rid of this error, or the refresh happens and the device still remains in the view, you should do a restart of your computer. Simply click on Start, then click on Shutdown and choose Restart for the option to restart your PC. When the computer starts, go to Device Manager and see if the device is still showing up. The computer reboot should have permanently removed the device.
If you accidentally deleted the hardware device, you will need to go through the process of reinstalling it. You can use the original installation disk that came with the device and walk through the installation steps recommended by the manufacturer to get the device installed again.
TipFor more information, please see: How to fix Hardware error #21