Unable to boot to the desktop after performing Windows Updates with error code 0xc000021a.

Original title: windows 8 error 0xc000021a

 

I do not have a installation disc to repair because i downloaded windows 8. It happend just after updated itself. Automatic repair does not work.

 

Question Info


Last updated March 24, 2018 Views 628 Applies to:
Answer
Answer

Hi Jesse,

 

Thank you for posting your query in Microsoft Community. 

 

From your description, it seems that you are unable to boot to the desktop after performing Windows Updates with error code  0xc000021a.

 

I would appreciate if you could answer the following question:

 

. How did  you perform automatic repair?

 

 

If you are unable to boot the computer in Normal Mode, then you may have to create a installation media using another computer. In order to create a installation media, you may refer the article: “How to create installation media for a PC refresh or reset” from this link:

http://windows.microsoft.com/en-us/windows-8/create-reset-refresh-media

 

After creating the installation media, I would suggest you to try booting the computer in safe mode using the installation media. Try the following methods.

 

Method 1:

 

Try booting the computer in Safe Mode and perform a Clean Boot.

 

Step 1:

 

Try booting the computer in Safe Mode.

 

a) Boot the computer using Windows 8 installation media.

b) In the “Windows Setup” dialog box that appears, set the Time and currency format, Keyboard or input method and the language to install and then click “Next”.

c) Click on “Repair your computer” from the lower left corner.

d) From the “Choose an option screen”, click on “Troubleshoot”.

e) Click “Advanced Options” in the “Troubleshoot” screen.

f) Click on “Startup Settings” in the “Advanced Options” screen

g) Click on “Restart” and wait for the computer to restart to “Startup Settings”.

h) In the “Startup Settings” screen, press the “F4” key on the keyboard to restart the computer in Safe Mode and check if you are able to boot the computer in Safe Mode.

If you are able to boot the computer successfully in safe mode, then try the Step 2.

 

Step 2:

 

Perform a Clean Boot and check if this issue is caused by any third party application.

 

A clean boot helps to eliminate software conflicts and to determine what is causing the problem. Perform a clean boot on the computer by following the steps given in the link:

http://support.microsoft.com/kb/929135

Now, you may try running the Windows Updates and check if the issue persists.

 

Note: After you have finished troubleshooting, refer the article “How to reset the computer to start as usual after troubleshooting with clean boot” for Windows 8, given under the section “More Information” to reset the computer to start as usual from the above link.

If you are unable to boot the computer in Safe Mode, then try performing an Automatic Repair and check if that resolves the issue.

 

Method 2:

 

Perform an Automatic Repair of Windows 8 using the installation media.

 

a) Boot the computer using Windows 8 installation media.

b) In the “Windows Setup” dialog box that appears, set the Time and currency format, Keyboard or input method and the language to install and then click “Next”.

c) Click on “Repair your computer” from the lower left corner.

d) From the “Choose an option screen”, click on “Troubleshoot”.

e) Click “Advanced Options” in the “Troubleshoot” screen.

f) In the “Advanced Options” screen, click “Automatic Repair”.

g) Follow the on-screen instructions to complete the Automatic Repair.

If the automatic repair did not work, then try the next method to perform a system restore using the bootable USB drive which you have created and check if you are able to boot into your computer.

 

Method 3:

 

Perform a System Restore from Advanced Startup Options and check.

 

To perform a System Restore, follow these instructions and check:

 

a) Boot the computer using Windows 8 installation media.

b) In the “Windows Setup” dialog box that appears, set the Time and currency format, Keyboard or input method and the language to install and then click “Next”.

c) Click on “Repair your computer” from the lower left corner.

d) From the “Choose an option screen”, click on “Troubleshoot”.

e) Click “Advanced Options” in the “Troubleshoot” screen.

f) In the “Advanced Options” screen, select “System Restore”.

g) Follow the on screen instructions to restore the computer to an earlier state when the computer was working fine.

 

Now check if you are able to boot the computer successfully.

 

Note: The System Restore restores the computer back to an earlier point in time, called a restore point. System Restore doesn’t change your personal files, but it might remove recently installed apps and drivers and also reset the recently changed settings on the computer.

 

Please do get back to us with the results of the above instructions and all the additional information regarding this issue.

 

For any Windows related issues please feel free to contact us and we will be glad to help.

 

 

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