C000021a errors are common blue screen errors that you may face on your Windows XP computer. You may encounter the following error message soon after your boot your Windows XP computer, even before the Windows login screen appears.
A common c000021a blue screen error message is:
“STOP: c000021a Fatal System Error has occurred”
Cause of the Error
The error may be caused due to any of the following reasons:
- An installation process adds mismatched Windows system files.
- An incompatible third-party utility or application is installed.
- A back up program that you used to restore the hard drive failed to correctly restore files.
- A service pack installation process fails to complete.
The Stop 0xC000021A error occurs due to failure of either Winlogon.exe or Csrss.exe. The Windows Kernel stops the system and raises the 0xC000021A error when it detects that either of these two processes have stopped.
Here are some of the tasks that you can perform to deal with the Stop 0xC000021A error.
Create Log and User.dmp Files
- Open the Start menu, select Run, type Drwtsn32.exe –I and then press Enter.
(A message informing you that Dr. Watson is installed as the default application debugger will be displayed.)
- Press OK.
- Next, at Start > Run, type Drwtsn32.exe and press Enter.
- In the Dr. Watson for Windows dialog box, select the Append to existing log file, Create crash dump, and Visual Notification checkboxes.
- When your computer restarts after the stop error, run the Drwtsn32.exe command again.
- Here, analyze the Dr. Watson log file and the user.dmp file to identify the cause of the error.
Fix Issues Related to the Winlogon.exe Process
Failure of the Winlogon.exe file is one of the most common causes of the stop 0xC000021A fatal system error. This error usually occurs when a buggy, third-party Graphical Identification and Authentication (GINA) DLL file replaces the original GINA DLL file that belongs to the Winlogon.exe process. This file is used in Windows to implement the authentication policy of the interactive logon options you see at the logon screen of your Windows XP system. The task of the GINA file is to carry out the user identification and authentication activities. The name of the Windows GINA DLL file is msgina.dll.
To check the current GINA settings for your computer,
- Run the regedit command to open the Registry Editor tool.
- Here, navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon registry entry.
- Check if the GinaDLL REG_SZ value is present.
If the value of this entry is anything other than MSGINA.DLL it implies that a third-party GINA file has replaced the original GINA file. The absence of this value indicates that your system is using msgina.dll as the default GINA DLL file.
If you find that the original GINA DLL file is replaced, you may try to resolve the error message by uninstalling any recently installed device driver updates or third-party software. To ensure complete removal, you may choose to use a reliable program uninstaller tool, such as Perfect Uninstaller, to remove this driver or software from your computer. Also, use a registry tool, such as RegServe to scan and fix any registry issues that may be behind the errors.
If this step fails, try to boot your system using the Last Known Good Configuration. To do this, restart your PC and keep pressing F8 until the boot menu options are displayed. Here, scroll down using the down arrow key and then select the Last Known Good Configuration option.