The CHKDSK utility incorrectly identifies and deletes in-use security descriptors

When you run the chkdsk command in fix mode, and you use the /F switch or the /R switch with this command, access control lists (ACLs) on some files may revert to their default values. This problem may occur if the volume contains more than 4,194,303 files. For example, this problem occurs in the following Chkdsk output:

This problem occurs because the Chkdsk utility may not find references to all the security IDs if the master file table is larger than 4 gigabytes (GB) or if there are more than 4,194,303 files on the volume. Therefore, the undiscovered security descriptors are reset.

We recommend that you immediately apply the appropriate service pack or hotfix on any computer that is currently vulnerable to the loss of security descriptors.

We recommend that you inventory servers and workstations in your organization and then install preventive software on any computers that are at risk. We recommend that you apply any preventive fix to new computers before you deploy the new computers for test or production use. We recommend that you inform server administrators, helpdesk administrators, and support professionals that they should install preventive fixes before the following operations are executed:

• chkdsk /F
• chkdsk /R
• autochk

Note IT operations guides should also install preventive fixes before these commands are executed.

Windows Server 2003

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.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart your 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 tool in Control Panel.

Windows XP

To resolve this problem, obtain the latest service pack for Windows XP. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

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

Even when this hotfix is installed, it is still possible for Chkdsk to reset permissions back to default settings. You can use the Vrfydsk.exe utility to determine whether real Security Descriptor file corruption occurs on a volume. You can save the Vrfydsk.exe utility output to a text file. If the resulting output file contains the following repair entry, the default security may be set on some files and directories.

For more information about the vrfydsk.exe utility, click the following article number to view the article in the Microsoft Knowledge Base: For more information, click the following article number to view the article in the Microsoft Knowledge Base: For more information about security descriptors, search Help and Support Center for "security descriptors."