The size of the GUID partition table (GPT) disk is not updated on a Windows Server 2008-based or a Windows Vista SP1-based computer after you use a disk management program to expand a logical unit number (LUN)

Consider the following scenario:

• You are running a Windows Server 2008-based or a Windows Vista Service Pack 1 (SP1)-based computer.
• To provide additional space on the computer's hard disk, you run a disk management program to expand the size of a logical unit number (LUN).

In this scenario, the LUN size is not updated after you run the disk management program. This issue occurs if you use a computer that includes GUID partition table (GPT) disks.

Note A master boot record (MBR) disk does not experience this issue.

The Partmgr.sys system drive expands the size of a LUN on a GPT disk by forwarding IOCTL_DISK_GET_DRIVE_GEOMETRY_EX control code instead of the IOCTL_DISK_GET_PARTITION_INFO_EX control code that is used with an MBR disk. However, the IOCTL_DISK_GET_DRIVE_GEOMETRY_EX control code does not provide the updated information about the LUN size. Therefore, this issue occurs only with GPT disks.

Hotfix information for Windows Server 2008

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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have Windows Server 2008 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2008, x86-based versions

Windows Server 2008, x64-based versions

Windows Server 2008, Itanium-based versions

Hotfix information for Windows Vista SP1

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.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix, you must have Windows Vista Service Pack 1 installed.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista SP1, x86-based versions

Windows Vista SP1, x64-based versions

Windows Vista SP1, IA-64 versions

For more information about IOCTL_DISK_GET_PARTITION_INFO_EX control code, visit the following Microsoft Web site:For more information about IOCTL_DISK_GET_DRIVE_GEOMETRY_EX control code, visit the following Microsoft Web site:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.