STOP: c000021a (Fatal system error)

Posted on 2000-03-15
Last Modified: 2013-12-28
I have a machine with Windows NT Workstation 4.0 and SP5, besides other applications.
The last thing I did was logon as local administrator and gave local administrator privilegies to an user from the domain, which is a common task.
I reboot, and the following error appeared, after the blue screen with the counting dots:
"STOP:c000021a (Fatal system error). The Windows Logon Process system process terminated unexpectedly with a status of 0x00000080 (0x00000000 0x00000000). The system has been shutdown."
The TechNet wasn´t very helpful...
Thanks in advance!!!
Question by:lalamia
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Expert Comment

Comment Utility
Try repairing the NT installation.  Insert you NT Setup disk and go through like an installation, but select the repair option and this should take care of your problem.

Expert Comment

Comment Utility
What happens if you press the space bar to get into profiles, and choose "L" for last known boot? Does that get you into Windows?

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Was this info helpful at all?
PSS ID Number: Q156669
Article last modified on 10-30-1999

The information in this article applies to:
 - Microsoft Windows NT Workstation versions 3.5, 3.51, 4.0
 - Microsoft Windows NT Server versions 3.5, 3.51, 4.0
A Windows NT Server or a Windows NT Workstation may stop with the following
   STOP: c000021a {Fatal System Error}
   The Windows Logon Process system process terminated unexpectedly with a status
   of 0xc0000034 (0x00000000 0x0000000)
   The system has been shutdown.
NOTE: The parameters in parenthesis are specific to your system configuration and
may differ each time.
The stop 0xC000021A is caused by a user-mode process that causes the Windows NT
operating system operations to come to a halt. Windows NT interprets this STOP
as a fatal error and the operating system will not continue. A memory dump from
this type of STOP does not contain much useful information without the proper
The solution to the STOP 0xC000021A lies in troubleshooting this STOP from an
application standpoint. Basic troubleshooting procedures apply. "Was new
hardware installed?" "Was new software installed?" And so forth.
Any applications loaded in user-mode memory space can cause this STOP. This
includes the native user-mode processes of Windows NT. Carefully review the
loaded software on this system and try to determine if any one of them may be
causing a problem. Follow these steps to help in isolating the cause of these
types of errors.
First, set up Dr. Watson to trap any user-mode application that may be causing
this problem. Dr. Watson for Windows NT is an application error debugger, which
is a program that detects application errors, diagnoses the error, and logs the
diagnostic information.
To properly set up Dr. Watson to trap user-mode problems, perform the following
1. Run <SystemRoot>\System32\Drwtsn32.exe-I. This will initialize the Dr.
   Watson program.
2. Run <SystemRoot>\System32\Drwtsn32.exe and select dump symbol table and
   create crash dump.
3. In Windows NT 3.51, copy the <CD-ROM>\Support\Debug\Symbols from the
   Windows NT Server CD-ROM to the %SystemRoot% of the failing system. To
   install symbols in Windows NT 4.0, use the Expndsym.cmd batch file.
4. When a Dr. Watson log is generated, use the log to determine what user mode
   process may be causing a problem. The Dr. Watson help file can be used in
   assisting in decoding the log file. If the Dr. Watson log does not contain
   enough information to determine the cause of the problem, the User.dmp file
   can be analyzed to determine the cause of the application fault.
NOTE: If the Windows NT system fails running a third-party application, this
problem should be directed to the third-party software vendor.
If a third-party software package was recently installed, and now the system
fails on booting with a 0xC000021A, try using the Last Known Good option at
start up. After Windows NT has started, remove the faulting application and
contact the third-party software vendor.
Set the GlobalFlag to 60000 in the registry. To do this, please see the following
Microsoft Knowledge Base article:
   ARTICLE-ID: Q147314
   TITLE : GlobalFlags for Windows NT 3.51
After setting this global flag, the systems memory dump will contain more
information on the faulting user-mode application. Making any kernel mode memory
dump more useful.
Additional query words: debugref 21A 0x21a
Keywords          : kbnetwork NTSrvWkst
Version           : winnt:3.5,3.51,4.0
Platform          : winnt
Issue type        : kbprb
Copyright Microsoft Corporation 1999.


Author Comment

Comment Utility
Lamentably, when the previous administrator did the NT installation, he didn´t create the repair disk.
Secondly, I tried choosing "L" for the last known profile, without any success.
And the solution given in the TechNet and attached by "sgenther" speaks about entering the failed system and making adjustments, but how can I do that if I can´t enter the system?

Expert Comment

Comment Utility
Thats only if you can get into the system then later get the error. I have a feeling this is gonna be a rebuild for ya.
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Expert Comment

Comment Utility
Try making a NT boot disk. You do that by going to a NT machine that works, and Formatting a floppy (which you MUST do in NT).

Next, copy the following files on it


Reboot and see what that does.
LVL 12

Expert Comment

Comment Utility
-Reload nt on top of itself and rejoing the domain.
LVL 23

Accepted Solution

Tim Holman earned 100 total points
Comment Utility
Let's face it - NT is shagged, and without a repair disk or working last known good, you're not going to be able to get it back up.

However - if you reinstall NT into ANOTHER directory on the system, it may give you a chance to take remedial steps to the original system to get it back up.

Author Comment

Comment Utility
Thx everybody for your suggestions, but as I was out of time, I had to reinstall NT , so when I opened my mail it was to late to try some other options...So I think Tim Holman was the closest one with his answer...

Expert Comment

Comment Utility
I had the same pdoblem with the STOP:c000021a(Fatal System Error)

I repaired my NT installation using the setup disks and CD-ROM. I proceeded as if I was performing an NT Setup. When the prompts asked me if I wanted to re-install, repair or quit setup, I chose setup.  The setup asked me if I wanted to check system, .ini, registry files, I said yes. Then the setup discovered a change in one one of my system files, then it wrote the correct file over the corrupted file. I had a successful reboot after this repair.

Expert Comment

Comment Utility
My earlier post had a mistake in it.  "When the prompts asked me if i wanted to re-install, repair or quit setup, I chose setup"  It should read I chose repair.

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