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When Windows PE fails to set up disk partitions

Windows Preinstallation Environment (PE) works with Remote Installation Server to help admins who must configure large numbers of XP and WinServer 2003 systems across a network. But sometimes the process goes awry.

Windows Preinstallation (PE) Environment makes life easier for administrators who must configure and manage large numbers of Windows XP Professional and Windows Server 2003 systems. PE works with Remote Installation Server (RIS) to let admins set up and install standard configurations for Windows systems across a network. This is much easier than having to visit each system to install the same configuration over and over.

But the process sometimes goes awry. When you use the Diskpart.exe tool to create partitions on a RAID set that includes raw disks, the system may fail to create the disk partitions. After about three minutes, you will get this error message: "The disk management services could not complete the operation."

If you quit Diskpart.exe and try again, you'll get the same error message. But if you restart the system in Windows PE and run Diskpart.exe again, the process will complete successfully.

What is happening is that the Volsnap.sys driver doesn't have any device object associated with it when Windows PE starts from a RIS server on a system that includes raw disks. In these circumstances, when Diskpart.exe creates a volume, the system can't find the Volsnap.sys driver, so the I/O Manager attempts to unload the Volsnap.sys driver. However, this operation fails because of an outstanding reference to the driver object. Unfortunately the failure doesn't remove Volsnap.sys from loaded modules list. This leaves things in a confused state and the confusion escalates when Diskpart.exe tries to create a volume.

As part of the volume creation process, Diskpart.exe searches the driver list for Volsnap.sys. When it doesn't find it, the system tries to load Volsnap.sys, but that fails because according to the loaded modules list, Volsnap.sys is already loaded.

Microsoft has introduced a hotfix for this problem. To use the hotfix on 32-bit systems you must have Service Pack 1 installed on Windows Server 2003. The 64-bit versions of Windows already contain the SP1 fixes.

Rick Cook has been writing about mass storage since the days when the term meant an 80K floppy disk. The computers he learned on used ferrite cores and magnetic drums. For the last 20 years he has been a freelance writer specializing in issues related to storage and storage management.

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