Error 0xc000021a and BSoD Blue Screen - All Windows Update Recovery Methods

BSoD - Blue Screen of Death, Blue Screen of Death is a problem only for experienced Windows users. If the programmer says that he has never encountered BSoD, the probability that he / she lies is 99%. BSoD errors are very popular and can tell you about the health and performance of your PC. One of them is the BSoD / STOP error 0xc000021a, which occurs when updating or reinstalling Windows.

Troubleshooting error 0xc000021a in Windows.

What does this error mean?

The error says that your computer has encountered a problem and needs to restart. It does not appear separately, but inside the "blue screen of death." This may cause serious problems damaging the internal structure of Windows. Often the error cannot be eliminated even after rebooting the PC. Error code 0xc000021a usually occurs on a Windows 10 PC after upgrading from a previous version of the OS or after starting a system restore. In this case, the BSoD contains the following information:

“STOP: c000021a {Fatal System Error}

Unexpected completion of the Windows Logon Process system process with a status of 0xc0000034 (0x00000000 0x0000000)

System shutdown completed. ”

Possible causes of the problem

In most cases, the system (Windows 10 and earlier versions) does not boot and along with the error 0xc000021a, a blue screen of death is displayed just after the update. There are two files that are the main cause of this error:

  • winlogon.exe - as seen from the file name, it is responsible for entering and exiting Windows. may be damaged due to inconsistency of system files, deleted or replaced by third-party software.
  • csrss.exe - owned by a Microsoft server or client, processes Windows 10 graphic instructions. It can be removed, damaged, or replaced by third-party software.

These two required files are not available if:

  • The system files were damaged during the installation of Windows.
  • Failed to download the update.
  • Incomplete software installation completed.

Less popular reasons:

  • Incorrectly configured driver of program files.
  • System file mismatch.
  • Restrictions by third-party software when running the OS.
  • Damage to the client / server runtime subsystem (CSRSS).
  • Damage to WinLogon.
  • Malware has entered the device.
  • Incorrect system files are installed or the system update process has failed / is still not completed.
  • Premature unloading of Wbemprox.dll.
  • Recently installed third-party software is not compatible with the operating system.
  • Damaged, outdated or incorrectly configured device drivers.
  • Not enough space in the system partition.
  • The Windows registry is corrupted due to software or system changes. This means that there are registry entries that are not cleared after application removal.

How to fix it

There are several proven ways to fix the 0xc000021a error in Windows. Try them alternately until you achieve the desired result.

Uninstall recently installed software

This solution is one of the most effective. First perform the following steps:

  1. Press the Windows key, and while holding Shift, press Power / Reboot. The download will start in recovery mode.
  2. In the recovery window in the menu "Recovery Options", select "Troubleshooting".
  3. Click Advanced Options, then Launch Options.
  4. Select Reboot.
  5. After the reboot, press the F7 key and in the appeared menu select “Enable Safe Mode”, then “Reboot”.

If you're lucky, the PC will boot onto the Windows 10 desktop. Then:

  • Click Start, type "programs" and select "Programs and Features."
  • Sort programs by installation date, then remove as many newly installed applications as possible.
  • In the left part of the window, find "View installed updates" - the installed OS updates will open.
  • Remove all recently installed updates.

After uninstalling recently installed applications / updates, reboot the system.

BIOS reset

Many users report that resetting the BIOS settings helped them solve the problem. Make it simple - you need to remove the CMOS battery from the motherboard for a couple of minutes. The method does not work with laptops, as their motherboards are not available. To reset the PC BIOS, do the following:

  • Turn off the computer.
  • Disconnect all power cables from the PC, making sure that the computer’s access to electricity is completely disconnected.
  • Open the case.
  • Locate the CMOS battery (somewhere on the motherboard) and remove it.
  • Wait 1-2 minutes and re-insert the battery.

Assemble the chassis, start the computer and see if it successfully loads into Windows.

Replacing all damaged registry files with backups

To use this method on Windows 8 and other versions:

  • Insert the Windows or USB installation disk into your PC and reboot it.
  • As soon as the download starts, enter the BIOS settings and rearrange the boot priority from the HDD / SSD to a CD / DVD or USB-flash. The BIOS boot instructions may vary, but will almost always be displayed on the first screen that appears during boot (with the name of the motherboard).
  • Save changes and exit BIOS.
  • Select a language and time zone, click "Next."
  • In the "Install Now" window, click "Recover Computer" / "Troubleshooting" / "Advanced Settings" / "Command Line", after which it will open.
  • Type c: and press Enter.
  • Then enter the commands one by one and press Enter after each one.
    • cd windows \ system32 \ config
    • dir
  • One after another for each document in the folder enter this command
    • ren (FILE NAME) (FILE NAME) .old

For example, ren SYSTEM SYSTEM.old is for the SYSTEM file. ren SECURITY SECURITY.old - for the SECURITY file.

  • Then, one by one, type in the command line, pressing Enter after each:
    • cd regback
    • dir
    • copy / Y SOFTWARE
    • copy / Y SAM
    • copy / Y SYSTEM

After that, close the command line, press EXIT, then ENTER. Remove the installation disk or USB from Windows and reboot the PC. check if it can boot successfully without BSoD and error 0xC000021A.

BCD Recovery

If your computer is unable to perform the installation of the update or restore the system, there is a high probability of removing the boot sector or damage it. Restoring boot configuration data, abbreviated BCD, can help repair corruption in the boot sector. Repairing bad sectors may allow the reinstallation process to begin. If you do not know how to do this, follow these steps:

IMPORTANT. Make sure you have a Windows 10 or USB installation disk.
  1. Insert the Windows 10 or USB installation disk.
  2. Reboot the computer.
  3. Go to the BIOS and rearrange the boot priority from the HDD / SSD to CD / DVD or USB.
  4. After downloading the files, select the language, date, time, layout, and click "Next."
  5. In the next menu, select “Restore PC” / “Troubleshoot” / “Advanced Settings”.
  6. Run a command prompt as administrator.
  7. Then, one by one, type in the command line, pressing Enter after each:
    • bootrec / FixMbr
    • bootrec / fixboot
    • bootrec / scanos
    • bootrec / RebuildBcd

Wait until the end of the process and restart the PC.

Removing Peripherals

Peripherals can cause serious problems with system files. The most logical reason is that they interfere with the download or update process. As a result, this interaction can lead not only to the “Blue Screen of Death”, but also to other problems. Regarding error 0xc000021a, it is necessary to ensure proper removal of all USB or DVD and other peripheral devices except the mouse and keyboard. First, turn off all devices in the device manager (joystick), then check the taskbar near the clock - if there is a “Safely Remove Hardware” icon, right-click on it and select "Disable ...". Reboot the PC and test its performance.

Download Last Known Good Configuration

You can try to download the latest successful configuration, which will try to use a previously error-free version of the registry on your system. To download this mode, follow these steps:

  • Restart or shut down the PC completely and then press the power button to turn it on.
  • Before the Windows logo appears on the screen, press F8 several times (just press, not hold it down).
  • On some laptop models, you may need to hold down the Fn key.
  • Once the system has booted into the Advanced Boot Options menu, select the Last Known Good Configuration from the list using the arrow keys.
  • Press Enter.

Hard Drive Performance Check

Finally, if none of the above steps worked for you, it may be that the hard disk is causing the error. Then you can run a hard drive diagnostics and check for bad or bad sectors. On the Internet you can find many third-party tools, but there is an alternative to Windows. To do this, the "Check for errors" is suitable, which will help determine the exact state of the HDD. If you are not sure how to do this, follow the steps below:

  • Open My Computer or Explorer.
  • Right-click the system partition and open "Properties."
  • Open the “Service” tab.
  • Select “Check for errors” and wait for the procedure to complete the scan.

Convert disk or partition from NTFS to GPT

To fix error code 0xc000021a in Windows 10, you may need to convert a partition or disk from NTFS to GPT. Perform the following steps:

  1. Turn off the device and insert the Windows installation USB or DVD.
  2. Boot your PC from USB or DVD in UEFI mode.
  3. In the Windows Installer, open a command prompt window by pressing Shift + F10.
  4. Type diskpart in a command prompt window to open the diskpart tool.
  5. Enter list disk to determine which disk to reformat.
  6. Select the disk to reformat by typing select disk on the command line.
  7. After that type clean, then press Enter. Next, type convert gpt to convert the disk from NTFS to GPT.
  8. Type exit and press Enter. Now you can close the command window.
  9. After converting a partition or disk from NTFS to GPT, you can continue installing Windows.
IMPORTANT. Choose Custom to choose the type of installation. The disk will be displayed as a single area of ​​unallocated space. Select this unallocated space, then click Next. At this point, Windows will start the installation.

If none of the solutions helped you or you know any other ways, share it in the comments under the article.