Windows XP Home c000021a Boot Error

Posted on 2005-05-16
Last Modified: 2012-05-05
After foolishly installing a freeware mp3 converter (Free Music File Converter 2.1.1 from, upon restarting my Dell Inspiron 8200 running Windows XP Home, I was greeted with the blue error screen showing the c000021a {Fatal System Error} message.  The next line had the error designation 0x0000138.

All attempts at a Safe Mode and Last Known Restore Point reboot from the F8 menu have produced the same error message.  My guess is that I need to remove the software, but as I cannot get into Windows this is proving difficult.  After searching this the Microsoft Knowledge Database, this site, and Google, here are the options that seem to be available:

Repair using the original XP Home CD (it came pre-loaded OEM)
Re-install XP Home

Which option is better and how would it be best to accomplish this?  This computer is used for work and, like everyone else, I have many previous files in my Documents and Folders directory which are not backed up.   I understand that this is an operating system problem that is separate from data files, but the Microsoft knowledge database has sections suggesting that some of this data could be lost from this directory upon re-install.

Also, if I would like to hook my hard drive up to another Dell Inspiron to take the files off before I attempt anything, what would be the best way?  I have never "slaved" a primary hard disk before to accomplish this.

Thanks to everyone for your advice and help.
Question by:nbl9q
    LVL 2

    Assisted Solution

    This is what I found about the error you're receiving in the Microsoft Debugging Tools:

    The STATUS_SYSTEM_PROCESS_TERMINATED bug check has a value of 0xC000021A. This means that an error has occurred in a crucial user-mode subsystem.

    This bug check will display a descriptive text message.

    This error occurs when a user-mode subsystem, such as WinLogon or the Client Server Run-Time Subsystem (CSRSS), has been fatally compromised and security can no longer be guaranteed. In response, the operating system switches to kernel mode. Microsoft Windows cannot run without WinLogon or CSRSS. Therefore, this is one of the few cases where the failure of a user-mode service can shut down the system.

    Mismatched system files can also cause this error. This can occur if you have restored your hard disk from a backup. Some backup programs might skip restoring system files that they determine are in use.

    Resolving the Problem
    Running the kernel debugger is not useful in this situation because the actual error occurred in a user-mode process.

    Resolving an error in a user-mode device driver, system service, or third-party application: Because bug check 0xC000021A occurs in a user-mode process, the most common culprits are third-party applications. If the error occurred after the installation of a new or updated device driver, system service, or third-party application, the new software should be removed or disabled. Contact the manufacturer of the software about a possible update.

    If the error occurs during system startup, restart your computer, and press F8 at the character-based menu that displays the operating system choices. At the resulting Windows Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time. If this does not resolve the error, try manually removing the offending software. If the system partition is formatted with file allocation table (FAT), use an MS-DOS startup disk to gain access to the computer's hard disk. If the system partition is formatted with NTFS file system, you might be able to use Safe Mode to rename or delete the faulty software. If the faulty software is used as part of the system startup process in Safe Mode, you need to start the computer using the Recovery Console in order to access the file. If a newly installed piece if hardware is suspected, remove it to see if this resolves the issue.

    Try running the Emergency Recovery Disk (ERD) and allow the system to repair any errors that it detects.

    Resolving a mismatched system file problem: If you have recently restored your hard disk from a backup, check if there is an updated version of the Backup/Restore program available from the manufacturer. Make sure the latest Windows Service Pack is installed.

    - Before you reinstall Windows XP, I'd try booting from the CD and using the Recovery Console to try to delete the folder teh software you installed is in, using the DOS shell to navigate. There are a few other options you have at the Recovery Console that might work as well. If none of those options work, I'd install XP Home from the actual disk, not the Dell Recovery CD (though you might have some additional options if you boot from the Dell Recovery CD). I hope that helps, and keep us posted k?

    LVL 13

    Accepted Solution

    I bought XP PRo about three months ago and still do not trust it since I have had to reinstall it two times.

    I now have now a slave drive just for a back up of data.

    I would suggest an easy way out that may cost a little money. Why not if all else fails and you are running out of time, purchase another HD, and make the existing HD a slave?


    Author Comment


    For all those who encountered the same problem, and have pulled up this page, here is how my scenario turned out.

    The two posts above from rheqium and gonzal13 were both correct in different ways.  The way the problem got fixed (not by me, but some professional IT guys), was to buy a new HD, upgrade my XP Home to XP Pro on the new hard drive, and slave the old hard drive to the new one.

    In order to fix the Windows Home 0021a boot error, I could have used the original XP Home disc to recover it or reinstall XP Home.  I did not do this as yet because of the fears that I would lose my data in the My Documents folder since Microsoft's Knowledge Base suggests this can happen.  I was fairly confident that my data was there, but I just couldn't get to it because of the boot error.  When I looked at my old drive using XP Pro on the new drive, I found that I could see and use everything except the "My Documents and Settings" folder.  I also found two fairly moderate viruses when I scanned with Norton, which I immediately removed.

    The reason why I couldn't use the "My Documents and Settings" folder is due to the security settings of the folder set up my Microsoft and/or XP Home when it is originally created (remember this folder is already premade when you load XP).  The ability to use this folder is set to the account that you set up in XP, and if this account is lost then the ability to get into this folder is lost.  I was told this is because the security is an NTFS format.  You can manually set the security of any folder to be like this, but I don't remember doing so (nor did I have the knowledge before this incident).  Therefore, any new account I setup will not have the proper security settings to access my old folder.

    In any case, the only way to remove the security settings was to actually hook the old drive up to an Apple G4 desktop, which does not see the NTFS security settings.  We then transfered the files via the Mac to an external HD (I got a SeaGate 300GB, pretty nice), and then the security settings were stripped away from the folder.  Now I can transfer the files back to my computer and see the folder just fine.

    Some lessons I picked up:

    1.  The correct way to think about your computer is not "if" it will fail, but "when".  As a result, you should plan accordingly for it too.  In other words, buy an external HD (or another internal hard drive) and backup frequently.  The nice thing about external hard drives now is that they have a one touch backup system where only the newly modified files are transfered.  Also, some come with Norton Ghost, which is great to make a perfect "image" of your hard drive in its current state.

    2.  Buy a second hard drive and designate one for your programs and one for your data.  Viruses and other nasty things/people almost invariably target programs, especially ones from Microsoft and other software giants.  Data is not crucial to the running of your machine, and therefore is not the primary target.  In my case, I would have simply wiped the hard drive with the problems and re-installed Windows and other programs while my data hard disk would have been unaffected.

    3.  With the internet it is now, assume that anything free or that says it is offering you something for free is trying to hack your computer.  My problems came when I downloaded from CNET/ which I have found to be a reputable site.  In other words, use firewalls, antivirus, anti-spyware, and if you are not super knowledgable like me, fork over the dough just so you don't have to go through this headache like I did.

    Alright, I hope my troubles will help someone in the future.  Thanks for all the help.
    LVL 13

    Expert Comment

    Another option that I use:

    Using Norton Ghost Ver 9, make an image of the HD onto the slave and then make incremental backups. This way I have the complete HD on the slave disk. I then can do incrementall backs up. Thus, I have a senario where both HDs cannot fail at the same time.


    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Highfive Gives IT Their Time Back

    Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

    Can I legally transfer my OEM version of Windows to another PC?  (AKA - Can I put a new systemboard in my OEM PC?) Few of us are both IT and legal experts but we all have our own views of Microsoft's licensing rules and how they apply.  There are…
    If you have done a reformat of your hard drive and proceeded to do a successful Windows XP installation, you may notice that a choice between two operating systems when you start up the machine. Here is how to get rid of this: Click Start Clic…
    To add imagery to an HTML email signature, you have two options available to you. You can either add a logo/image by embedding it directly into the signature or hosting it externally and linking to it. The vast majority of email clients display l…
    In this sixth video of the Xpdf series, we discuss and demonstrate the PDFtoPNG utility, which converts a multi-page PDF file to separate color, grayscale, or monochrome PNG files, creating one PNG file for each page in the PDF. It does this via a c…

    759 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    10 Experts available now in Live!

    Get 1:1 Help Now