On a Windows XP-based computer, you use the Backup Utility (Ntbackup.exe) to back up files that are encrypted by Encrypting File System (EFS) on an NTFS volume. Later, when you use the Backup Utility to restore these files, the files cannot be restored correctly. Additionally, the backup report shows several errors. Moreover, the following event is logged in the System log:

Event Type: Error
Event Source: NTFS
Event ID: 55
Description:
The file system structure on disk is corrupt and unusable. Please run the chkdsk utility on the volume "Drive_letter:"

After you restart the computer, the Autochk.exe program starts and discovers data corruption on the volume.

This problem occurs only when you restore certain files that are encrypted by EFS. For example, this problem may occur when you restore some encrypted files on a computer that has the 2007 Microsoft Office system installed.

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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.

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, submit a request to 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 XP Service Pack 2 or a later service pack installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other 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 XP with Service Pack 2, x86-based versions

File name	File version	File size	Date	Time	Platform
Ntfs.sys	5.1.2600.3356	576,384	22-Apr-2008	09:43	x86

Windows XP with Service Pack 3, x86-based versions

File name	File version	File size	Date	Time	Platform
Ntfs.sys	5.1.2600.5585	576,384	22-Apr-2008	13:45	x86

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

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

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