How do I solve an 'lsass.exe' application error shown at the Windows XP boot?

It just happened to me. I did a windows update and when it booted back up I was getting the lsass.exe - Application Error. The Application failed to initialize properly (0xc0000006). Click ok to terminate the application.

After that, Windows blue screen. I tried booting into safe. Same message. I tried booting to last good config. Same message.

At that point, I could see from all your posts that I was sunk but I thought I'd try one more thing. I removed the hard drive and plugged it into my EZ-Connect. It came up fine on my pc. I ran a check disk and it took almost an hour. Then I copied the lsass.exe from another XP PC to the harddrive. I put the harddrive back in the pc and it booted right up. I couldn't believe it. But it worked!!!

I am afraid you will not be able to fix this one except with a reinstall. I would try the Repair installation that harrymc links to above, that's what we call an in-place upgrade. But I've had this issue before and once you mess with the Local Security Auth Server it is usually a lost cause.

If none of the other answers work, you could try Microsoft's Malicious Software Removal Tool, ComboFix or Stinger - all of which deal with common viruses (which is what this sounds like).

Google is your friend at times like this too! There's always someone out there who has experienced something similar.

I would start by going into safe made.

Next, go to command prompt and type

SFC /SCANNOW

This should scan and fix most of the serious issues with Windows that would otherwise take a reinstallation.

The next thing I would do is use Autoruns from Microsoft / Sysinternals and disable all non Microsoft services that I am not sure of until the problem goes away.... After services, I would go to the other tabs and do a similar job of deleting anything that looks dodgy.

If the problem still exists, I would go for a reinstall.

This is usually caused by a virus that is trying to load each time an application is initialized. The actual exe or dll may have been removed by a vrius scanner, but the registry key still remains. Theat is what is causing lsass to fail. There is a registry key that needs to be edited. but you can't load windows to get into the registry. you'll need a remote registry editor, like BartPE, or Ultimate Boot CD for Windows. THIS IS SERIOUS STUFF AND CAN F@#$ YOUR COMPUTER, so if you don't have COMPLETE CONFIDENCE that you know how to safely edit the registry, take it to a professional.

Once you gain access to the registry, back it up, then search for AppInit_Dlls. renamed it AppInit_Dlls.old. Then create a new string key named AppInit_Dlls. leave its value blank, empty. Save your registry changes and reboot into safe mode with F8. Once windows loads, install MalwareBytes scanner and do a fullscan. You will need to reboot to kill all viruses, and probably have to run the full scan a second time in normal boot mode (not safe mode).

Then install a serious anti-virus anti-malware scanner, nothing from McAfee or Norton Symantec will be good enough, they are just shills for suckers. thank you internet.

This error with lsass.exe file seems to be temporary, because when Windows throws this error in the startup when you shut down the computer and after 4-5 minutes when you start it again, it fixes itself. :) So it is a time sensitive issue.

I do not know the reason why this error occurs, but it might be interference with some software or virus to throw this error.