How to Fix Blue Screen Error Code 0xC000021A in Windows 10/11?

You will have to reinstall Windows.

I have a Lenovo Laptop, Windows 10. I TRIED this fix but it still takes me back to the error screen. I also tried to do this but doing Safe mode with the Command Prompt so I can do the scan but it stills goes right back to error screen. PLEASE HELP.

thanks for letting me know.

the iso disc worked - took a few hours for everything to work through - but so far after spending several hours putting software back on - moving files where I want them the computer and OS seem to be working fine - very time consuming - for those contemplating a fresh new clean install - all your files will be saved in a “windows.old” folder so you won’t lose anything, at least I didn’t

sorry didn’t get a chance to get back to you - got busy yesterday
i’ll try to download it this morning

How exactly do i do a complete reinstall - I’ve tried the above options and others and can’t get anything going - i downloaded the windows 10 to a disc I think but the computer wouldn’t boot from the disc - but then again - i’m clueless to some of the in depth details - any set of instructions on exactly how to do a complete clean reinstall? thanks

You have no errors when your PC Can’t turn on, you need to address the “pc turning on” issue first before you get to this .

i had tried both the method but it is still not working

It don’t work with F7 only. I have a x200m asus notebook and i don’t think pressing Fs alone would
work.

You cannot use it with Fn. Try pressing 7 only.

Should fn button be pressed together with the F7 button? I can’t select F7 alone.

Hi. Is it normal that after preasing F7 the screen turned black and until now it’s black. Please help. My laptop is not turning on now after pressing F7.

I need help. Got the blue screen. (then before i checked here) i tried a system reset. Now it tried to back up files- it stopped and a screen came up that said files could not be read it left a screen that asked me to terminate??? I am a computer dummy, please help.

After installing the fresh copy, disable windows updates.

I tried both solutions but don’t work for me … I’ve to install fresh copy of windows every day! What may be the problem?

So on trying this I just get the blue screen again saying it needs to restart after gathering error data. I’m being told now I will probably have to uninstall and reinstall losing files. Any other successes, I’ll be watching.

Okay. I have most of it saved on different external drives, but wanted to check and make sure before everything disappeared.

Are you able to reset windows 10, when you go to reset it from the advanced options, you have the option to keep files or remove files. If i were you and the files weren’t important for me, then i would remove them and do a reinstall.

I had this error come up about a month ago after accidentally hitting keys on my computer, but I was able to fix it with a system restore. All of a sudden, it happened again after what appears to have been a Windows update last night while in sleep mode. System restore won’t work, and neither will hitting F7 in the advanced options. I’m not sure what I need to do since I don’t have Windows 10 on backup. If I download it and re-install 10, will all of my files get deleted or will everything be okay?

I am having this problem as well, and I own a Cyber Cafe. The problem is with my master computer and the only way of fixing it was to refresh/reboot. I have done this 4 times over the past month (very frustrating). On the last time, I used Method #1, which worked. My question is this…if my computer shuts off unexpectedly or I do a restart, this is when I get the error code. If I shut down, the computer is fine when I turn it back on. If I did Method #1, has the problem been permanently fixed? or will this error come up again upon a restart? (I’m afraid to try) Thank you.