According to Microsoft, both Windows Vista Service Pack 1 and Windows Server 2008 SP1/RTM can run into very rare problems when it comes down to integration with hardware components connected via a PCI Express interface. The Redmond giant described an issue occurring only at restart in which cards failing to play nice with a power management feature of the Windows client and server platforms will cause the operating systems to become unresponsive.

"Consider the following scenario: you have a computer that is running Windows Server 2008 or Windows Vista Service Pack 1; the computer has a Peripheral Component Interconnect (PCI) Express interface; you have at least one PCI Express card that does not fully support Active State Power Management (ASPM) inserted; you restart the computer. In this scenario, an internal error may occur during restart. For example, a CPU IERR error may occur. Additionally, the system may stop responding," Microsoft informed.

All editions of Windows Vista SP1 and Windows Server 2008 are affected by this issue. However, the problem is not sufficiently widespread to justify the release of an update. According to the software company, statistics indicate that, even when all the ingredients are into place, only 1 in 500 reboots will result in Windows becoming unresponsive. In this context, a hotfix is available addressing the scenario, but end users will have to contact Microsoft directly in order to access it.

"This problem occurs approximately one time in every 500 restarts. Therefore, you usually experience this issue only when you are running restart tests. However, the risk of this problem occurring increases significantly if the following conditions are true: you apply hotfix 952681 on the computer; you insert PCI Express cards that do not fully support ASPM into all available PCI Express slots," Microsoft added.