A .pst file backup fails even when there is sufficient free space on the destination disk on a Windows Vista-based or Windows Server 2008-based computer that has the Pfbackup utility installed

Consider the following scenario. On a computer that is running Windows Vista or Windows Server 2008, you have Microsoft Outlook and the Microsoft Outlook Personal Folder Backup utility (Pfbackup) installed. Then, you run the Pfbackup utility to back up the personal folder file (.pst file) to a disk. In this scenario, you receive an error message that indicates insufficient free space on the disk for this backup operation. However, when you check the free space on the disk, you find that there is sufficient space for the backup if the old .pst file is overwritten as expected.

For example, assume that you have a disk that contains 100 megabytes (MB) of available free space and a 200-MB copy of the backup .pst file. When you try to perform a new backup for the .pst file on this disk, you receive a "Not Enough Space" error message. However, you expect the old .pst file to be overwritten during the backup operation, and this should produce sufficient free disk space for the backup operation.

Note This problem does not occur in Windows XP.

This issue occurs because the copy engine in Windows Vista and in Windows Server 2008 uses a different disk space calculation algorithm.

In Windows Vista and in Windows Server 2008, the copy engine checks the available free space on the destination disk during the preparation phase. If the destination disk has insufficient space, the copy operation fails. The free space is calculated by assuming that no file is being overwritten. Therefore, you may receive the "Not Enough Space" error message even when there is sufficient space disk if the old file is overwritten.

A hotfix is available to resolve this issue. After you apply this hotfix, the Pfbackup utility will delete the existing file in a file replacement scenario. Therefore, the backup operation is performed successfully.

Hotfix information

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.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

To apply this hotfix, you must have Windows Vista Service Pack 1 or Windows Server 2008 installed.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other previously released hotfixes.

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 and Windows Server 2008 file information note

The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately . MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. The security catalog files (attributes not listed) are signed with a Microsoft digital signature.

For all supported x86-based versions of Windows Vista and of Windows Server 2008

For all supported x64-based versions of Windows Vista and of Windows Server 2008

For all supported Itanium-based versions of Windows Server 2008

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

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Vista and for Windows Server 2008

Additional files for all supported x86-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported x64-based versions of Windows Vista and of Windows Server 2008

Additional files for all supported Itanium-based versions of Windows Server 2008