Windows 10 Error 0xc000021a

[Zeurth]

Hello, I'm currently completely trapped by this error. I can't boot up to safe mode, disabling the drive signatures didn't work. I don't know.
I've tried sfc /scannow and get access denied.
chsdsk gives me write protected and I've tried system restore, which has failed.
windows reset with files does not work and as I'm trying to keep them I haven't tried a full reset.
oh and dism commands have not worked as well.
Any other suggestions? I do have a usb for bootable options.
Thanks for any help that can be provided.

[Boggin]

Method #5 in this article looks promising if you have Win 10 install media - https://appuals.com/how-to-fix-error-0xc000021a-in-windows-8-and-10/

Disregard anything to do with Reimage.

You can create Win 10 install media on any other computer if you haven't already done so by using this website after reading the instructions.

https://www.microsoft.com/en-gb/software-download/windows10

If using an USB and you have an UEFI BIOS then you will need to disable Secure Boot in the BIOS to boot from it.

You can access the BIOS in Win 10 by pressing and holding F2 as you switch on.

After the USB has loaded and you have navigated to the Install screen, click on Repair your computer bottom left.

[Zeurth]

Method #5 in this article looks promising if you have Win 10 install media - https://appuals.com/how-to-fix-error-0xc000021a-in-windows-8-and-10/

Disregard anything to do with Reimage.

You can create Win 10 install media on any other computer if you haven't already done so by using this website after reading the instructions.

https://www.microsoft.com/en-gb/software-download/windows10

If using an USB and you have an UEFI BIOS then you will need to disable Secure Boot in the BIOS to boot from it.

You can access the BIOS in Win 10 by pressing and holding F2 as you switch on.

After the USB has loaded and you have navigated to the Install screen, click on Repair your computer bottom left.

Thanks for the response.
Only issue is I'm using a laptop with a bios that has a password on it.
A company laptop bios password so there's no way to get into bios.
But will try.
Edit: It didn't work.

[Zeurth]

Are there any usb bootable programs that would help? Just curious.

[Boggin]

As it is a company laptop then you will have to take into their IT department or for the company to deal with it if they don't have an IT department.

However, there is only one disk that I know of that can help to perhaps get you back in and that is a Kaspersky Recue Disk but it can take a number of hours for it to scan the system - it really depends upon what caused the machine not to boot.

I can't remember if you need to change the boot order for it to boot up with that disk, but you can give it a try if you like.

I have my laptops set to check the DVD and USB drives before the HDD should I need to recover mine.

https://support.kaspersky.co.uk/viruses/rescuedisk

Use the Graphics option and you will need to Ethernet connect so that it can update its Definitions.

The first time I used it on mine, when it completed, it initiated a chkdsk /f and the second time, when I took the disk out on completion - power shut down - it started up okay when I switched on.

Before you try that, see if a cold boot will get you back in.

If the battery is accessible, remove that and the AC then press the power button for approx. 30 secs and try it again.

When you said those steps didn't work - did you mean that you were able to get into the BIOS ?

[Zeurth]

As it is a company laptop then you will have to take into their IT department or for the company to deal with it if they don't have an IT department.

However, there is only one disk that I know of that can help to perhaps get you back in and that is a Kaspersky Recue Disk but it can take a number of hours for it to scan the system - it really depends upon what caused the machine not to boot.

I can't remember if you need to change the boot order for it to boot up with that disk, but you can give it a try if you like.

I have my laptops set to check the DVD and USB drives before the HDD should I need to recover mine.

https://support.kaspersky.co.uk/viruses/rescuedisk

Use the Graphics option and you will need to Ethernet connect so that it can update its Definitions.

The first time I used it on mine, when it completed, it initiated a chkdsk /f and the second time, when I took the disk out on completion - power shut down - it started up okay when I switched on.

Before you try that, see if a cold boot will get you back in.

If the battery is accessible, remove that and the AC then press the power button for approx. 30 secs and try it again.

When you said those steps didn't work - did you mean that you were able to get into the BIOS ?

Sorry I wasn't clear, I bought this laptop off ebay but the password for the bios was changed so there is no taking it to their IT.
However I can choose what I boot from not boot order.
When I tried the cd \windows\system32\config it told me the path didn't exist.
Trying the kaspersky now.

[Boggin]

I'm not sure where you are trying that cmd but if you can boot with other media then it must already be set to check those first before the SSD/HDD.

Good luck with Kaspersky.

[Zeurth]

I'm not sure where you are trying that cmd but if you can boot with other media then it must already be set to check those first before the SSD/HDD.

Good luck with Kaspersky.

Sorry for being so unclear. I'm able to hold f9 for boot options and select the boot device.
As for the cmd, I'm able to get to the windows advanced options without using the media installation usb boot. so I don't need it to access it.

Edit: I've got kaspersky running now!

Thanks man, I'm running the scan now so by the time I'm back it'll be done.
I also since I love the tweaking repair program have backups to my registry so if this fails, how would I go about using it?
 Thanks so much.
If I do get it working, I will of course write a detailed reply about the process for future users.

[Boggin]

To use the registry back ups in Windows Repair, boot into Safe Mode with Networking and open the program and click on Backup Tools.

Click on Restore under Registry Backup then on the Restore Registry tab.

You will then need to use the dropdown to click on the backup you want to restore with but do not select one that is too old.

You can then hit the Restore Now button.

A word of caution though - under no circumstances run Windows Repair v4.0.10 on Windows 10 as there is a bug in it that will take out the MS Solitaire Collection.

Shane, as far as I know is working on a fix for it but for the moment once it's gone - it's gone and only a system image will restore it.

A restore point or the registry back up restore won't.

I'm not sure if this article will help you with the password problem - https://www.iseepassword.com/reset-windows-10-password.html

[Zeurth]

To use the registry back ups in Windows Repair, boot into Safe Mode with Networking and open the program and click on Backup Tools.

Click on Restore under Registry Backup then on the Restore Registry tab.

You will then need to use the dropdown to click on the backup you want to restore with but do not select one that is too old.

You can then hit the Restore Now button.

A word of caution though - under no circumstances run Windows Repair v4.0.10 on Windows 10 as there is a bug in it that will take out the MS Solitaire Collection.

Shane, as far as I know is working on a fix for it but for the moment once it's gone - it's gone and only a system image will restore it.

A restore point or the registry back up restore won't.

I'm not sure if this article will help you with the password problem - https://www.iseepassword.com/reset-windows-10-password.html

I can't get into any type of safe mode is the only issue, was hoping I could drag and drop from kaspersky's registry editor.
I have a back of my registry from an outdated windows repair program so it shouldn't have the solitaire collection issue but even if it did, I wouldn't mind.
I really don't think malware is my issue but I ran it while I was out to only find out the data base was corrupted so I'm going to try to reinstall the iso and hopefully get it running tonight before bed.
As for the password I know my password, just not the bios password but I don't need to use bios to change boot device so it's fine.

[Boggin]

Is it possible that taking out the CMOS battery for about 5 mins could reset the BIOS ?

If you post the make & model of your machine, I'll have a Google to see if I can find a strip down tutorial in how to replace the CMOS battery, but on some models the battery is soldered in.

I don't know what the Kaspersky disk does beside malware scan to get a system back up and running again but it resolved two black screens for me following failed restore points.

The first time it took about 9hrs to scan the Win 7 system and then I closed it down as prompted and when I came back from making a cup of coffee, I noticed it was running a chkdsk which fixed it.

The second time, while the scan was much quicker even though it was on a much larger HDD, I removed the DVD, power shut down and the machine booted fine when I switched back on.

I'm not sure how you have ended up with a corrupt database though.

[Zeurth]

Is it possible that taking out the CMOS battery for about 5 mins could reset the BIOS ?

If you post the make & model of your machine, I'll have a Google to see if I can find a strip down tutorial in how to replace the CMOS battery, but on some models the battery is soldered in.

I don't know what the Kaspersky disk does beside malware scan to get a system back up and running again but it resolved two black screens for me following failed restore points.

The first time it took about 9hrs to scan the Win 7 system and then I closed it down as prompted and when I came back from making a cup of coffee, I noticed it was running a chkdsk which fixed it.

The second time, while the scan was much quicker even though it was on a much larger HDD, I removed the DVD, power shut down and the machine booted fine when I switched back on.

I'm not sure how you have ended up with a corrupt database though.

Well I installed another HD in it and the laptop works.
Also as for opening it up, I wouldn't feel comfortable doing it.
andddd Kaspersky rescue disk using their to usb program, it keeps getting corrupted database and the fix I found won't work.
I'll keep looking.

[Boggin]

I haven't found any definitive fix for it yet - this is the first time I've seen this reported, but Google is awash with similar experiences.

So can you go wherever you want now with that HDD in ?

[Zeurth]

I haven't found any definitive fix for it yet - this is the first time I've seen this reported, but Google is awash with similar experiences.

So can you go wherever you want now with that HDD in ?

I only had one hard drive slot so I used it to test the hardware to make sure that wasn't the issue and it wasn't.

I did end up getting into the hard drive I've been trying to!

I used Hiren’s BootCD to boot to their mini windows xp version.

I opened to the hard drive list, right clicked the hard drive with the data in order to use command prompt.

(since it was from the drive I didn't get a write protection.)

I did a chkdsk but not sure if that contributed to me being able to boot into it.

Then proceeded to drag and drop my registry back ups into the registry.

Afterwards I had to use the hiren's bootcd usb in order to select the hard drive since it was stuck on intel's boot agent but I got in.

Any suggestions on everything to run in order to stop this from happening just in case shutting down leads to the same thing?

[Boggin]

You could create a repair or install disk to boot up with and create a system image so you wouldn't have to go through Windows to restore.

To restore an image from an external HDD you need to boot up outside of Windows to select the image option from Troubleshoot.

Is it too late to send this machine back to the seller as it has an unknown BIOS password on it which restricts you to its full operation ?

That's perhaps something you wouldn't necessarily have been aware of until later.