“Unknown Hard Error” Pop-Up Dialogs After Crash in Windows XP

I was using Visual Studio.NET 2005 on my Windows XP box last night (don’t flame me – I also program in Java and have several Macs), when suddenly the machine just restarted itself for no apparent reason; no blue screen, nothing – just a reboot.

When it started again, i got a pop-up dialog at the login screen. The title bar said “DfrgNtfs.exe – System Error”, and the message in the box was the unbelievably helpful “Unknown Hard Error”.

I tried looking in the system Event Log to see if I could find any clues there… – oops! I got the same “Unknown Hard Error” popup dialog – this time, with “mmc.exe – System Error” in the title bar. I tried opening a command prompt – nothing happened.

In order to try to read the crash dump file (C:WINDOWSMinidumpMini120105-01.dmp), I downloaded the microsoft free Windows debugger – WinDbg – as described in this good article:


However – when I try to install it, I get another “Unknown Hard Error” popup, with “msiexec.exe” in the title bar (starting to see a pattern, here…??)

I googled, and found several people saying it could be a hardware problem – notably hard disk or ram – so I did a full disk check – no improvement. I then figured that maybe the crash was caused by some other problem, but that it must have left some system files in a corrupted state, which, in turn, caused the pop-ups.

I eventually found a discussion group where someone (unfortunately, I didn’t save the link) recommended the windows command-line command: sfc /scannow – that checks all the win system files for corruption (and possibly bribery), and repairs them from your Windows XP install disk if problems are found. I ran that from the “start menu -> run” dialog, and some of the popups stopped…, well…, popping up (notably the DfrgNtfs.exe ones), but i still got them when trying to view the event log or trying to install software.

Finally, I found the answer. The files that the System, Application and Security events are written to (the ones you view from the Event Viewer) had been corrupted – so I guess whenever I tried to do something that would create an entry in one of these logs, I got an error. The solution was found on this page:

“How to Delete Corrupt Event Viewer Log Files”

…which basically says – disable the event logging service in the “Services” dialog; reboot; delete the following files from C:WINDOWSsystem32config: AppEvent.Evt, SecEvent.Evt and SysEvent.Evt (or rename them as a backup); set the event logging service back to “automatic” startup; reboot

That solved all my problems…


  1. surferlist said,

    February 7, 2007 at 7:05 am

    Thanks very much guys!!
    Works for Windows 2000 also.

  2. Unknown Hard Error - FileFront Gaming Forums said,

    June 19, 2007 at 5:54 am

    […] pop in your winxp cd and run the repair option so you can boot into windows. Then, I found this link that suggested it could be corrupt event system notification logs and when you write new logs to […]

  3. Ripsnub said,

    November 22, 2007 at 7:37 pm

    I had this same issue today….but no other information to go along with the “Unknown Hard Error” box. Very helpful indeed. I had just installed new printer drivers and uninstalled old Canon printer drivers when the problem first showed. Then the error would show up, click OK, pop up again, repeat, then system basically froze except for the unknown hard error pop. ctrl-alt-del restarted system. Ran scan disk and check disk/f – all was good. I will try the event log fix you discussed above and hopefully that will resolve it.

  4. Björn said,

    January 17, 2008 at 3:09 am

    Thanks a million^^

  5. Thorsten said,

    February 24, 2009 at 2:49 pm

    And you solved with your post my problems. Thanks alot for that.
    Best regards Thorsten

  6. Boss said,

    February 26, 2009 at 4:13 am

    Thanks for this. Solved my issue straight away

  7. Leslie said,

    February 24, 2011 at 3:26 pm

    I had similar problems followed by system not booting. I found that the RAID controller was at fault. I purchased a RAID controller kit from http://stores.velocitytechsolutions.com/-strse-361/H1813-Dell-Poweredge-perc/Detail.bok.
    The fix required all three components, battery, cache RAM, and Key. After installation the system still would not boot but a tech created a BART disk for me, booted the system and ran CHKDSK /R which repaired the system and now everything is running ok. Have not gotten another Unknown Hard Error.

  8. Maqbool ur Rahman Aawan said,

    June 26, 2011 at 6:33 am

    Many many thanks for great guidance. Its, too, was my first time in life that I received this Error[ Hard Error]. and got it solved in your precious guidance. I have been searching the net for solution since last Wednesday 22nd,June,2011.
    And found it here…. Just got lucky…. Thanks.

  9. Chris said,

    April 9, 2013 at 2:42 pm

    You are simply amazing. Thanks a million. Saved my workstation from having to be reloaded and spending days of downtime. 🙂

  10. ogy said,

    June 15, 2013 at 5:04 am

    thank a lot

  11. adnan said,

    October 1, 2013 at 1:40 am

    my hard drive shows unknown during the windows xp installation.
    what is the solution

  12. Vebri said,

    February 15, 2015 at 5:46 pm

    Thanks bro. You safe my ass today.

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