Windows 10 updates come out almost every once in a while, and the latest KB5021233 update that was just launched last Tuesday, Microsoft has confirmed that for some Windows 10 devices, a blue crash screen may appear after the update, and display 0xc000021a error message, the cause is currently being investigated, which means friends who haven’t upgraded yet, please remember to wait for a while. If you update and encounter this problem, there is also a temporary solution, and I will sort it out for everyone below.
Slow down before updating!Microsoft confirms Windows 10 latest KB5021233 causes blue crash screen on some devices
Since the release of the Windows 10 KB5021233 update last Tuesday, on foreign Microsoft forums and Reddit websites, users have responded to blue crash screens and 0xc000021a error messages, as Christopher Dut mentioned: ” After the 21H2 automatic update, a blue screen appeared when restarting for the first time, and it reappeared after restarting, and using the automatic repair function did not fix it.” He then tried many methods, but none of them worked:
There is also another tylo leonidas, who has encountered it for 3 consecutive days. After a lot of troubleshooting, he can’t figure out the reason, and every time he is away from the computer, it can be seen that the blue error screen is irregular. , it is very troublesome, especially for people who often need to leave the computer for output, half of the output will make people want to smash the computer:
In the post of Microsoft announcing the new version update in the Reddit forum, many users also reported that they encountered the 0xc000021a error message: 
For this reason, Microsoft has confirmed this problem on the official website, which may be caused by the file version mismatch between hidparse.sys in system32 and system32/drivers in the Windows folder, which may cause signature verification failure during cleanup:
Microsoft also provides a temporary solution, but you need to enter the Windows Repair Environment (Windows RE) and copy the hidparse.sys file from the system32drivers folder to system32 to avoid signature verification failure during cleanup (click me to read the instructions):
- You will need to enter the Windows repair environment. If your device has not automatically booted into WinRE, see the tutorial on entering WinRE.
- Select the Troubleshoot button.
- Select the Launch Recovery, Troubleshooting, and Diagnostic Tools button.
- Select the Advanced Options button.
- Select the Command Prompt button and wait for the device to restart (if necessary).
- Your device should reboot into a command prompt window. You may need to log in to your device with a password before you can get to the command prompt window.
- Run the following command (important: if Windows is not installed to C:windows, you need to modify the command according to your environment): xcopy C:windowssystem32drivershidparse.sys C:windowssystem32hidparse.sys
After the previous command finishes, type: exit - Select the Continue button.
- Windows should now boot as expected.
Microsoft also added that it does not recommend following any other workarounds other than those suggested above. We do not recommend deleting hidparse.sys from the WindowsSystem32 folder.
Source: BLEEPING COMPUTER