An update to the Windows Kernel fails to play all that well with Windows Vista Service Pack 1 causing the operating system to restart randomly. Microsoft informed that KB932596, an update designed to improve Kernel Patch Protection in the 64-bit versions of the Windows client and server operating systems, is in fact responsible for scenarios in which x64 versions of Vista SP1, Windows Server 2008 and Windows Server 2003 are rebooting at random.

"A computer that is running an x64-based version of Windows Server 2003, of Windows Vista, or of Windows Server 2008 randomly restarts and then generates a Stop error. The Stop error code may be 0x0000001E, 0x000000D1, or another Stop error code. This problem occurs after you install update 932596 on the computer," the Redmond giant described the symptoms.

Kernel Patch Protection, or PatchGuard, is a technology specific of the 64-bit variants of Windows platforms, both client- and server- side, and is set up to prevent all third-party interventions into the core of the operating systems. PatchGuard is first and foremost a security mitigation against rootkits but, at this point in time, it prevents all changes of the kernel.

The developers of security solutions which are used to hook into the kernel, a practice still generalized with the 32-bit versions of Windows, have had the most to suffer because of Kernel Patch Protection. However, with Vista SP1 Microsoft made available an application programming interface permitting legitimate developers to build an intimate connection between their security solutions and the core of the operating system.

KB932596 is nothing more than an update to PatchGuard, and a hotfix is already available, resolving the random restarts and the stop errors. Users will either have to contact Microsoft directly or wait for the update designed to specifically address the problems, because the hotfix is offered only to affected users.

"A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix," Microsoft added.