After you start an attended installation of Windows Server 2008, Setup does not correctly create an MSR partition

After you install Windows Server 2008 or Windows Vista Service Pack 1 (SP1) in unallocated space on a GPT disk, the Microsoft Reserved (MSR) partition is not automatically created. As a result, you cannot convert a basic GPT disk to a dynamic disk.

An MSR partition is not created automatically when you install Windows Server 2008 or Windows Vista SP1 to unallocated space on a GPT disk that already contains an Extensible Firmware Interface (EFI) system partition.

To prevent this, use the Disk Configuration window during installation to create a partition in the unallocated spaces. The installation will automatically reserve space for an MSR partition. If this problem occurs after you have completed the installation, use one of the following options:

Option 1

If unallocated space exists before the data partitions are created, use the Diskpart command prompt utility to create a 128 MB MSR partition. For more information about the Diskpart command prompt utility, click the following article number to view the article in the Microsoft Knowledge Base:

Option 2

If you cannot create an MSR before the data partitions are created, follow these steps:

1. Format the disk.
2. Restart the Windows installation media.
3. Create an installation partition from the Windows setup disk configuration page.
4. Install to the newly created partition.

Steps to reproduce the problem

Create an EFI system partition on a GPT disk that has no other partitions. Install Windows Server 2008 or Windows Vista SP1 in unallocated space on the disk by using Windows Setup. Make sure that the following conditions are true:

• You have a GUID partition table (GPT) disk.
• The GPT disk has an Extensible Firmware Interface (EFI) system partition.
• The rest spaces of the GPT disk are unallocated spaces.
• You start an attended installation of Windows Server 2008.
• In the Disk Configuration window, you select the unallocated spaces for the installation.
• You receive a warning message that states that no Microsoft Reserved (MSR) partition has been found.
• You select the option to continue the installation.
• The installation tries to create an MSR partition.

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