message on bootup - stop c000021a {fatal system error} the windows logon process system process terminated unexpectedly

I was installing Windows XP upgrades when my PC did a reboot, but I got the message: stop c000021a {fatal system error} the windows logon process system process terminated unexpectedly. I can F8 to the safe mode selection screen, but none of the selections will allow it to start windows - it returns to the error message.
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Maybe a SAM file problem.
Boot from CD and log on to recovery console.
copy C:\WINDOWS\repair\SAM C:\WINDOWS\system32\config\SAM
jglaAuthor Commented:
It won't boot from CD. I got the 6 floppy setup from the MS website to try to boot that way to reinstall XP, but when disk 1 stalls at "Setup is inspecting your hardware configuration"
Take a look at this page:

Here is the description for error 21A:


This occurs when Windows switches into kernel mode and a user-mode subsystem, such as Winlogon or the Client Server Runtime Subsystem (CSRSS), is compromised and security can no longer be guaranteed. Because Win XP can’t run without Winlogon or CSRSS, this is one of the few situations where the failure of a user-mode service can cause the system to stop responding. This Stop message also can occur when the computer is restarted after a system administrator has modified permissions so that the SYSTEM account no longer has adequate permissions to access system files and folders.

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The page also references a couple of MSKB article concerning the problem, namely:
GoBack Causes a Stop Error C000021a
Internet Explorer Maintenance Policies May Cause an Access Violation in Winlogon
Check these

Error Message: Stop c000021a {Fatal System Error} The Session Manager Initialization System Process...;en-us;317189

Security Accounts Manager Initialization Failed" Error Message When You Start Windows XP;en-us;316751 

Stop 0x21a" Error Message Occurs If You Download a RIPrep Image;en-us;308299 

or try reinstalling windows xp

Reinstallation of XP:;en-us;Q315341


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I think this is file or disk error. Find a way to run chkdsk.
jglaAuthor Commented:
Reinstallation of XP finally did it.
I would like to know this ..

If reinstalling did the job and I also suggested the same , can you let me know why grade B

rerun windows xp setup from cd, then choose to install xp on the same partition, as previously installed to.

xp will recognize a previous installation, and ask if you want to Repair or Install, select Repair.
problem solved.

then install latest service pack.

this method is simpler than running recovery console, especially if you're not familiar with Recv. Console.

Got the same problem. Did a repair and the system worked fne, but after installing all the patches Windows Update wanted me to install I had to reboot and got the error message again. I am repairing XP again and will then try to determine which patch causes the problem.

Update: I reinstalled Windows and tried applying the patches...I discovered that KB826939 ( causes the problem but unfortunately..that is a rollup-update which consists of more than 25 different updates. One or more of these cause my system to hang, but it's impossible to determine which one exactly and how I can work around it :(
I got the 21a error message today after uninstalling KB824141.  I hope this helps in tracking down the culprit.
KB824141 is not the culpret!

My system crashed last weekend.  At first, I suspected it was the hard disk, but that proved to be incorrect (thank god).  This site put me on to the idea of a corrupted Windows XP file (or files).  

I repaired Win XP and reinstalled all the critical updates, plus the recommended upgrades for XP (but none of Microsoft's driver updates).  This included KB824141.  Everything has been working fine for 5 days running.

Incidentally, speaking with the folks at Dell Technical Service, they confirmed that they have had numerous calls about this condition, but have not uncovered a cause either.

Hope this helps.
Further to my last post, KB826939 is not the culpret either.  It took on mine and again, I've been up and running for five days straight.

It is important to have a good clean line when downloading and to be sure your anti-virus program is turned off when doiwnloading and installing patches.  Otherwise the file might get corrupted.
ran into this problem today. After being able to login as another DOMAIN user, My solutiion was to copy the users profile and then rename the old profile from example DOMAIN\USER to DOMAINE\USEROLD and the have the USER log in as a "new"user and copy desktop files and fav's over to the new profile. Worked like a charm.
how did you do that? i am kind of a fool on this theme so could you please explain me?
I had this problem as well and the it was caused by bad RAM.
I swapped out the RAM and it was OK
I think is the video drivers from windows update. I used an old version of the video driver from the DELL site and it worked, NEVER EVER UPDATE to the newest video drivers that windows xp gets from microsoft or the newest driver from DELL, it makes DELL's computers to reboot and reboot.etc.
In fact, it is abad idea to use any driver that is not supplied by your computer's manufacturer since the generic version available through any other site (including Micosoft Updtaes) may not have the modified code that your computer manufacturer has written into the update that is specific to its configurations.  Learned this the hard way a few years ago.
This happened to me yesterday Dec 16th.  As of the 14th I was uptodate on my patches minus SP2 (it kills my VPN and firewall needed for corp access)  Yesterday I only installed 2 patches, but since I can't get into the machine I can't see which two caused the problem.  All I know is that they were not available before the 13-14th.

I will try to re-install XP for the fix. I hope that works.
I just had an easy fix for this.  I received a customer's laptop with the same error.  I did the F8 while booting and selected Last Known Good.  Problem solved.
Last Known good did not work for me.  SP2 on a Dell Inspiron Laptop, all nice and FUBAR thanks to M$ leaving more flaws in their updates.  And don't even tell me to turn off my antivirus (as I did that before rolling out the updates).
I got the same error (Stop C000021a) after I installed XP service pack 2 and restarted. I then booted with the XP CD and selected the repair option and restarted and go this message "This copy of Windows need to be activated". Guess now I have to call Microsoft, or is there a work around?
I installed a Sound Blaster Live! card and I got the message too.
I had to do a re-install to fix it.
What a waste of time!
Running into the same stop error after installing Diskeepr 9 pro.   No fix yet.
I have posted a separate thread about this issue and never had a satisfactory answer. I still get the STOP error from time to time, erratically (perhaps one or two boots in ten.) Usually after some hardware change, like adding a hard drive or removing one.
It seems like a bug in Windows, and Microsoft sure as hell isn't saying anything about it.
Although getting a bluescreen STOP error may be due to an incompatability among drivers, I hate to say this, but more often than not, it is due to buggy software as a result of some corruption due to trojan, adware, etc.  Adaware, Spybot, etc were only of limited use.  

In my case, the real cure was to strip everything off my Dell 600M hard drive and do a clean install of windows, office, etc.  The only thing I resinstalled was my data.  That was in January and since then no bluescreens.

For the record, I use only valid software and I am very care where I browse and what I download.  My antivirus (Norton Corporate 9.0) is always up to date, as are my Microsoft and Dell critical updates.  And I never download drivers from Windows.

'nuff said.
You may be right - but my experience was that I reinstalled Windows / Office / applications, and everything seemed fine for the first twenty or thirty reboots. Then one day BANG - out of the blue (if you'll excuse the pun) - the problem was back - and ever since then it graces me with its presence from time to time. Often twice successively. I just have to keep resetting till it goes away, which shows that it's not a driver issue, or it would be consistent!
Here's a dopey set of questions...
1.  How big is your RAM?  I wonder if the ulti-tasking is overwhelming the system
2.  Have you checked to see whether the RAM is working properly?  There is downloadable software to test the RAM and see whether it is fully functional
3.  Was your a complete install or an upgrade?  From what I understand when you build an upgrade, it can cause problems that don't happen with a complete software install.
4.  Have you tried to run a series of anti-spyware checks just to be sure you aren't downloading the same problem each time?  I have found you need a "cocktail" of all 3 majors: Adaware, Spybot and Microsoft's new Beta 1 - run sequentially just to be sure.

As I said a couple of dumb questions from someone who's been there.  Let us know how you make out.
Answers to weldjame's questions:
1. RAM? 1Gb of DDR533 RAM
2. Not only have I tested the RAM, I have physically replaced the modules.
3. It was a fresh install on a formatted disk.\
4. Yes, I use all 3 majors and BullGuard as well - I assume my system is clean.

As I keep repeating, the puzzling thing is the inconsistency of the issue. If it was repeatable I could try to track it down. But nine times out of ten the system boots without any problems! Sometimes the problem happens after a minor hardware change, but sometimes there is no change and it still happens. Very queer ...
Looks like you've done everything I would do.  As I said, these were long-shots, swinging for the fence.

I only hope it's not your video card or worse, your motherboard beginning to break down.

Did you say you spoke with the manufacturer's help desk?  For what it's worth, I do believe this is a hardware problem that like fruit, hasn't fully ripened yet (lucky you)!

I'll look forward to seeing the resolution when you find it.  Best of luck.
We have begun receiving these same errors. We set up six machines...5 Dell Latitude D600's and 1 Dell Latitude D610. We have Automated Updates enabled to run at 3:00 AM. We left 3 machines on overnight and 3 turned off. The three that were left on all had the blue screens while the three that were turned off are working fine. We are pursuing this as a means of resolving this issue.
video card drivers from windows is screwing up dell machines, if you can rollback the drivers the machine will work again.
The machines had been running fine up until that point. The image on all 6 is the same and include the Dell drivers for all hardware.
but I believe that windows update, brings a new driver for the video card that screws up dell video drivers, it happened to me and when I go in safemode and rollback the video driver I get the DELL back to work. Could you verify that with one of your machines?
We can't even boot into safe mode. I have someone here working on it trying to roll back individual patches one at a time within the recovery console. Is it possible to roll back drivers from within the RC?
Now that you mentioned it, I think I did a fresh installations and told the damn windows update to never ask me again about video drivers. This happened to me like 1 year ago, if you want to see how it messes up one of your dell pc that is currently working tell it to run windows update and just get a new suggested video driver from the list it shows you and BANG! no more dell.
This is all very interesting but beside the point - I am not running a DELL, my video drivers have not been upgraded by Microsoft, and the problem is intermittent - If I could produce it at will, I would at least be able to try different solutions.
I would strongly suggest that at least with Dell PC's one should never use drivers from anyone else but Dell.  If you go on their site you can register for driver update notifications and decide when you get them whether to install or not.  I use Microsoft only for critical updates to windows and office and sometimes for suggested updates to windows and office.  That's it.

I understand that both IBM and Gateway users have experienced the same thing (e.g. never to use generic drivers via Microsoft).

Good luck.
We were unable to replicate the problem. We have since gone back a rev on the image, re-run all MS updates and re-burned the image. Unabe to find the source of the problem.

Found the following.. suggest you give it a try..

The newest Critical Patches can be the reason for the error, please
uninstall KB893066, KB890923, KB890859 and KB893086

Please follow the procedure suggested by microsoft to solve BSOD problem from the latest windows update.

1. Insert the Windows XP startup disk in your floppy disk drive or insert the Windows XP CD in the CD drive or in the DVD drive, and then restart your computer.

Note When you receive the following message, press a key to start your computer from the Windows XP CD:
    Press any key to boot from CD

Note Your computer must be configured to start from the CD drive or the DVD drive. For more information about how to configure your computer to start from the CD drive or the DVD drive, see the documentation that came with your computer or contact the computer manufacturer.

2. When you receive the Welcome to Setup message, press R to start the
Recovery Console.  Note Multiple options will appear on the screen.

3. Select the Windows XP installation in question.  Note You must select a number before you press ENTER, or the computer will restart. Typically, only the 1: C:\Windows selection is available.

4. If you are prompted to type an administrator password, do so. If you do not know the administrator password, press ENTER. (Typically, the password is blank.)

Note You will not be able to continue if you do not have the administrator password.

5. At the command prompt, type cd $ntuninstallKB.........HERE THE NUMBER OF THE PATCH.....$\spuninst, and then press ENTER.

Note After you complete this step, you cannot stop the removal process.

6. At the command prompt, type batch spuninst.txt, and then press ENTER.

7. After the Patch is removed, then press ENTER, and uninstall the Next.
   Please uninstall (Thanks Murray S. from

You may also be able to apply this same solution to any recent update that could be causing a boot problem.

Good luck.
Thanks for this... although now I am almost 100% sure it was a hardware issue... I put the processor into a brand new machine, which failed the very first time Windows started - long before any updates were applied. I then had several more boot problems, to the point where I had to do a repair install because Windows woldn't start at all. I was then told that I could no longer activate the product because the legal activations had been exceeded... I reactivated over the phone, got the machine running again, and then - the dreaded Winlogon.exe startup service problem.
I have since changed the processor, and rebooted the machine many times without any issues.... So perhaps Case Closed?
ah, yes... sounds like a WinXP Hardware Change Activation-ism.

Good to hear it's resolved.
This (0xc000021a) STOP screen occured after I enabled Boot Magic.

The system will still boot OK if I select Win2k (else you wouldn't be seeing this!).
The system offers me a choice of Win2k and WinXP, but via what's on the boot.ini file - not the Boot Magic fancy screen, but the m/s plain black & white screen. If I select XP I get the fail situation. If I select the W2k, then I complete the boot process OK into w2k.
Something seems to have happened with the boot master record maybe?
How do I get XP again please?

     I don't know about the others, but I was never able to resurrect XP. Since my problems occurred during testing of an image, I simply went back, applied all of the most recent MS updates and turned off Automatic Updates. We now push our updates through Altiris, although the users can also pull the updates themselves directly from Microsoft. This BSOD only occurs on machines that have Auto Updates enabled.

Perhaps I'm fooling myself -- but I'm quite convinced that this (in my case) is a Boot magic thing.

I think I need the advice of a boot sector expert?
I consider the topic closed with no points awarded. Definitely a faulty processor, which Intel has replaced. I have never seen the error again since I replaced the processor.
I received this error message after installing th KB890859 update wich reffers to some kernel problems. I've already reinstalled WinXP 3 times and will now try to uninstall the patch using the recovery console wich is really the quickest way, al other solutions are too time consuming or are for more advanced users.
Ryan_RIT Systems AdministratorCommented:
This error has also come up after installing Office 2007 on domain PCs. The BSOD doesn't occur when I unplugthe network cable, which is my current workaround.

For any interested - the relevant question is here: http:Q_23295042.html
After boot from installation CD and "R" (recovery console)- just run CHKDISK /R and the problem will be fixed.
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Windows XP

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