What if you are unable to access safe mode as well? Last good known config also ends with the same error and then just reboots if 'ok' is selected. Is it time to call it a day and just repair the O/S?

I am in the same boat as chakatak. I cannot access my computer, even in safe mode and get the same error message. I am scheduled to take my computer to my friend that fixes all my problems on Sunday, but if anyone can help me fix it before then, I would be very grateful.

While many have had a different cause, the fix for me was to change the Memory usage from "cache" to "programs." System Properties-Advanced-Performance settings-Advanced-Memory usage.

I got the Lsass.exe system error this morning, "The endpoint format is invalid." After disabling all startup programs and services in safe mode didn't work, I took the suggestion here that the cache was to blame and changed my custome pagefiles to system managed, didn't work. Removed them completely(helps to have 1GB RAM) and changed the memory usage from "System cache" to "Programs." Joy, successful boot.

At this point I got a notification that the system had just been updated. MS broke my machine, again. Re-enabled the 768MB pagefile on the 1GB partition I had for it, still booted fine, twice. Added a system manged pagefile to the second drive and changed the memory usage back, lsass.exe error was back. Removed the page file again, no help. Switched them memory usage again back to "Programs" and it began normal booting again. Added pagefiles, still good.

The hardware has not changed in over a year, and the only software recently installed was a game and a Zone Alarm update two weeks ago. It is possible that spyware was involved, but it wasn't anything like Spyware Stormer. It would have had to be something that happened with little or no user intervention. I also pulled the drive and scanned the disk for errors and defragmented it with a Vista PC, nothing found, no help. CCleaner found a bunch of invalid registry entries, but nothing relevant, mostly MUI. Spybot and Adaware found zilch, so I am doubting malware, but I'll be running an AVG scan tonight. Just need to finish our taxes right now. Teach me not to procrastinate next year. If only we had the "FAIR TAX" instead.

Moral of this story is that Windows changes too much. Whether it is Spyware or Microsoft themselves, these changes are too difficult for the different hardware and software vendors to keep up with. We need a more stable, non-changing codebase. To update or not to update, which is worse? Usually malware, but when the system won't boot, what do you tell people? Take your shots?

Had to type that twice. I seem to have a problem staying logged in.

whats up everyone, i have run into this problem on many differnt computers and here is how you fix it.

If you can boot into Safe Mode:
right click on "My Computer"
go to "Properties"
Click "Advanced"
Click "Settings" in the Performance Box
Click "Advanced"
Change Memory Usage to "Programs"
Reboot

If you cannot boot into Safe Mode:
(I have not tested this, so use at your own risk)
But hey, you cant boot anyway, so what do you have to loose.

Use recovery disk to get into recover console or find some other way to run a command prompt on the drive that is having the issue.
The type the following command:
REG ADD HKLM\System\CurrentControlSet\Control\Session Manager\Memory Management /v LargeSystemCache /t REG_BINARY /d 0x1
reboot

That should change the same key that was changed in the first steps

If this works, signup for an accoutn here and let us know, this windows issue has gone on long enough, and Microsoft is not addressing this widespead problem, we need your feedback.

Peace,

Adam

For me, the Gateway didn't start this error until we tried the max memory upgrade (to 2 gb) that crucial.com recommended. With both sticks in, we got the error. With one stick in, and one stick of the factory 256 memory, we got the error. We put back both sticks of factory 256, and no error.

I think I'll try Nar's fix to change the memory usage with the factory memory installed, then switch to the new 1 gb sticks, unless anyone thinks that would prove to be a problem.

I'll let you all know how that turns out unless someone talks me out of trying it.

adambeazley - you are a star! I hit the same problem (after much tinkering as part of speeding up XP - classes.cnet.com) so re-booted (safe mode w/networking) and found your post. I followed your instructions and everything worked as before. Thanks for the tip.