An update to Microsoft's anti-malware software for Windows XP has caused systems to crash in the latest issue for those running the ageing platform.

The first update to Microsoft's System Center Forefront Endpoint Protection since the Windows XP end of support date on 8 April held a nasty payload in a bug that crashed the program due to changes in the MPEngine dynamic link library.

Users of Microsoft Technet blamed malware, and suspicion also fell on Microsoft itself breaking compatibility after announcing it would no longer be responsible for ensuring it.

However, some users opposed that view. One wrote: "We cannot blame Microsoft because we've been told a year ago that their support [of] Microsoft Windows XP ends."

In reality, the problem came about due to a bug in the way the program handles behaviour monitoring, the service that scans networks for unusual behaviour patterns.

By disabling this service either through the interface, a registry hack in safe mode, or a group policy update, it is possible to keep using Endpoint.

Microsoft has confirmed that it will release a patch to fix the problem, but that has not stopped disgruntled users from suggesting that the "bug" was deliberate.

A recent report from Avast Antivirus said that 23.6 percent of its users would continue to use Windows XP, with 21 percent oblivious to the end-of-life cut-off. Just 15 percent planned to upgrade their operating systems and only five percent planned to upgrade their hardware. An overwhelming 85 percent of affected users said that they expected their anti-malware software to protect them.