When both of the following conditions are met, event ID 55 may be logged.
You have a file server that is running Windows 7 or Windows Server 2008 R2.
The cluster size (also known as the allocation unit size) for an NTFS volume is larger than 4 kilobytes (KB).
Specifically, the following event is logged in the System log:
Log Name: System 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:"
Additionally, because of file system corruption, the server may crash.
This issue occurs because the BITMAP attribute of the NTFS metafile cannot roll back when an exception is raised after you modify the metafile. When the system tries to extend the BITMAP attribute, there is no transaction in progress, and the attribute snapshots are purged before the system starts to process the exception. In this situation, file corruption may occur, and NTFS event ID 55 may be logged.
To resolve this issue, we have released hotfixes for Windows 7 or Windows Server 2008 R2. Check out the prerequisites of the hotfix.
Note This hotfix does not fix the existing file system corruption. Therefore, you have to run the Chkdsk command together with the /f or /r parameter after you apply the hotfix.
For more information about the Chkdsk command, see Chkdsk.
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 the problem described in this article. 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 website:
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.
To apply this hotfix, you must have Service Pack 1 installed in Windows 7 or Windows Server 2008 R2.
To apply this hotfix, you do not have to make any changes to the registry.
You must restart the computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace a previously released hotfix.
The global version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows 7 and Windows Server 2008 R2 file information notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table:
Windows 7 and Windows Server 2008 R2
Windows 7 and Windows Server 2008 R2
GDR service branches contain only those fixes that are widely released to address widespread, critical issues. LDR service branches contain hotfixes in addition to widely released fixes.
The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows 7 and for Windows Server 2008 R2" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows 7
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
For all supported IA-64-based versions of Windows Server 2008 R2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Usually, event ID 55 is logged when file system corruption occurs. The file system corruption occurs when one or more of the following issues occur:
A disk has bad sectors.
I/O requests that are delivered by the file system to the disk subsystem are not completed successfully.
For the issue that is described in this article, event ID 55 is logged because the I/O requests are not completed successfully. When this issue happens, the bitmap information that manages file records proves to be inconsistent. Therefore, the user can’t find the file and folder properties. In this situation, the file index experiences an inconsistency, but in fact there is no file corruption. However, because of the logged event, it may seem like file corruption has occurred.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684Description of the standard terminology that is used to describe Microsoft software updates
Additional file information
Additional file information for Windows 7 and for Windows Server 2008 R2
Additional files for all supported x86-based versions of Windows 7