A bad Microsoft Security Essentials (MSE) update may have the primary reason behind hamstrung and slow Windows XP systems, new user reports indicate.
Users started reporting yesterday that their Windows XP systems were crashing after an MsMpEng.exe application error. The issue starts as soon as Windows XP system is booted. The MSE error read: “MsMpEng.exe application error. The instruction at “0x5a4d684d” referenced memory at “0x00000000″ The memory could not be read”.
One of the users on Microsoft community forum noted that this error “leaves the computer in an unusable state, because it won’t go on anymore, whatever you try, and the only solution is to disable MSE or uninstall it completely”.
Temporary solutions were to disable the MSE service or uninstall it completely; however, both the options are highly unsafe and actually takes away the little protection that Windows XP is left with after its end of life.
The issue is seemingly due to a bad definition / scan engine update noted one of the users on the community forum. “It was a bad definition / scan engine update and they released a fix already this morning. Update your MSE definition files, reboot, and you should be fine.”
“Definition update 220.127.116.11 seems to have fixed the issue for Microsoft Security Essentials running on Windows XP systems. I downloaded it via the Windows Update Catalog site and then pulled out the X86-all-am_delta_01c5765ad7d884b780031a7c2f72fc4c30b14094.exe to apply to my 32-bit XP systems and the error was resolved.”