Hello dear viewers all;
On this video,
I will show you how to fix windows boot loop with blue screen error message saying that:
"Your pc ran into a problem and needs to restart"
with error code: 0xc000021a
in windows 8, windows 10
and windows 11.
According to Microsoft, the followings are the most common sources for 0xc000021a boot loop
1- A corruption in system files
2- A failure in installing windows updates due to computer shut down
3- An installation of incompatible third party app or driver
4- A backup or cloning program that used to restore a hard disk didn't correctly restore files.
The possible solutions will be different according to the error source, which include:
- Repairing corrupted system files and bad disk sectors
- Trying automatic startup repair tool
- Removing the incompatible app or driver using Safe Mode
- Restoring system to a previous restore point
- Restoring or repairing registry files.
On this computer, all suggested solutions were failed to fix 0xc21a issue except the registry restoring method,
as the registry files were corrupted due to interrupted installation of windows update.
However, I will show you all suggested solutions,
so you can fix your issue if you have another root source or if there is no registry backup in your computer.
First solution: How to repair system files:
If the recovery environment was enabled in your computer,
the system will try to repair start up files and then open automatic repair menu as shown.
From this menu, select Advanced Options to enter into windows recovery environment
If the recovery was disabled or corrupted,
you have to create a bootable USB of windows using your mobile
or in another computer in order to boot into advanced recovery menu
Refer to video description to learn how to create a bootable USB and how to boot from it.
Select troubleshoot option and then advanced options
Open command prompt
Execute the following three commands to rebuild disk sectors and BCD file:
BOOTREC /FIXMBR BOOTREC /FIXBOOT BOOTREC /REBUILDBCD
If you get "Access is denied" error message,
execute the following command and then try again: BOOTSECT /NT60 SYS /FORCE
Now type BCDEDIT and press Enter to show the BCD data
Type this command to restore system health locally: DISM /IMAGE:D:\ /CLEANUP-IMAGE /RESTOREHEALTH
Replace the D with the letter of winnows partition in your computer
Now, execute the following command to check and repair system files integrity: SFC /SCANNOW
To check and repair bad disk sectors, execute the following command: CHKDSK D: /F /R /X
Replace the D with the letter of winnows partition in your computer
if you are booting from a USB drive,
you can download the automated patch script from descriptions and execute all mentioned commands by one click.
in addition, the script
will try to replace the corrupted or missed files from the bootable USB if there is no a backup copy for the missed or corrupted files in your computer.
Now, close command prompt and then click Continue button to restart into Windows 10 or Windows 11 operating system.
Second solution trying automatic start of repair tool:
From advanced recovery options,
click on Start-up Repair to start the tool.
In addition to repairing startup,
this tool can help you to determine the root cause of the error by opening the SRT log file.
To open the SrtTrails text file,
navigate to the directory of log file according to what you will see on the start-up repair screen. D:\windows\system32\logfiles\srt\srttrail.txt
In my case, the root cause was boot critical file corrupt, with error code ox2.
Third solution: Removing the incompatible app or driver using safe mode
If the problem appeared after installing a new app or updating existing app or driver,
you can remove the problematic app by booting into safe mode as followings:
Select Start-up Settings option and then click on Restart.
Press F4 from keyboard to boot into Safe Mode
If there is a corruption in registry or recovery files,
the computer will fail to boot into safe mode.
In safe mode, you can either remove the app or recent windows update,
or remove the recent driver installation according to what you think is the source of the error.
To remove installed driver, do the followings:
Right click on "Start" icon and select Device Manager option
Right click the problematic device and then select "Uninstall Device" option.
If you are not sure which drive is the source of the issue, skip this step.
If you think the issue is related to recent app you have installed,
you have to remove it as followings:
Press "Windows logo + R" keys from keyboard
Type Control and press Enter
Change "View by" into Category option
Select "Uninstall a Program" option
Click on "Installed on" column to sort apps according to installation date
Right click the problematic app and select Uninstall option.
If you think the recent windows update is the source of the error,
click on "View Installed Updates" option from left panel.
Locate the latest windows update or package according to its installation date and then uninstall it.
After that restart your system to see whether the issue fixed or not.
Fourth solution: Restoring system to a previous restore point:
If System Recovery was enabled and you have a valid Restore point,
this solution will probably fix the issue unless the registry files are corrupted in your computer.
To restore your system, do the followings:
Select "System Restore" option and then click Next.
If the System protection was disabled in your computer,
you will see an error message saying that, "No restore points have been created on your computer’s system"
Select the restore point from the list and then click on Next
Select Finish option and then click on Ok or "YES" to start restoring process
If you are unable to proceed with restoring process or if the restoring process started but failed to fix the issue,
then the issue is probably related to registry corruption,
so you have to repair or restore your registry files as instructed on the next solution.
FIFTH SOLUTION: RESTORING OR REPAIRING REGISTRY FILES:
There are many sources that can corrupt the registry data,
such as viral attack, manual modification or third party app;
However, the most common source for registry corruption is when the computer powered off while installing windows updates.
If you have an older windows 10 or new windows 10 or windows 11 with enabled registry backup,
then you can restore the backup manually to fix your issue as followings:
Open Command Prompt
Type Notepad and press Enter
From File tab, select Open option
Click on "This PC" icon and then open windows partition
Navigate to this path: D:\Windows\System32\Config\RegBack Replace the "D" with the letter of winnows partition in your computer
Change "File of Types" option to All
If there are files with a file size that is not equal to zero for each one,
then you are lucky, and you can copy the registry files to Config folder one by one after renaming existing files as followings:
Copy the "Default" file and back to Config folder
Rename "Default" file int Default.old and then paste the copied file into the Config folder
You will not be able to see the old file with the new name and the new file you have pasted until you have done a Refresh for the folder.
Open RegBack folder again and repeat previous steps with all registry files.
It’s worth noting that the corrupted registry will probably lead to failure of many recovery options,
such as DISM or SFC, System restore or system reset and Booting to Safe Mode.
After copying all registry files, close Command prompt
Click on Continue option to restart your system into windows 10 or windows 11.
As you can see, this computer booted successfully after replacing Registry files without blue screen error.
If you do not have a backup copy of the registry files saved in the RegBack folder,
try to repair the registry using new registry files as shown in the other video in the video description below.
If you were able to solve this blue screen error using any of the methods mentioned in this video,
do not forget to add a comment with the number of the method that helped you for the benefit of others.
If you encounter any problem while applying any method,
try using another method, or add your question in a comment, and we will try to help you.
Thanks for watching!
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