File Corruption Occurs on an NTFS Volume with More Than 4 Million Files

This article was previously published under Q229607
This article has been archived. It is offered "as is" and will no longer be updated.
When you create and delete files on an NTFS volume that holds more than 4 million files, you see file corruption that may show up in one of the following ways:
  • Deleted files continue to be displayed on the drive.
  • Files that you have not deleted are no longer accessible.
  • A pop-up message is displayed reporting that corruption has been detected on the drive and requesting that you run CHKDSK.
This problem occurs when the Master File Table (MFT) has grown larger than 4 GB, which may happen when you have more than 4 million files on your computer. When you delete a file whose MFT entry is beyond the 4 GB point under these conditions, an error in calculations causes the wrong entry to be marked as available. If this entry contains information for another file, and new files are added to the volume shortly after the deletion occurs, the entry could be re-used causing the file it actually referenced to be lost.

Windows NT Server or Workstation 4.0

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or the individual software update. For information on obtaining the latest service pack, please go to:
For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

Windows NT Server 4.0, Terminal Server Edition

To resolve this problem, obtain the latest service pack for Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in theMicrosoft Knowledge Base:
152734 How to Obtain the Latest Windows NT 4.0 Service Pack

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows NT Server version 4.0, Terminal Server Edition Service Pack 6.
More information
Information on all files in an NTFS volume is stored in the MFT. The MFT contains one or more an entries for all files on the system. In addition, the MFT maintains empty or unused entries which can be used for newly created files. When a file is deleted, it's entry is marked as being unused so that when a new file is created, the file system can re-use the entry.
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Article ID: 229607 - Last Review: 11/02/2013 19:00:00 - Revision: 4.0

Microsoft Windows NT Server 4.0 Standard Edition, Microsoft Windows NT Workstation 4.0 Developer Edition, Microsoft Windows NT Server 4.0 Enterprise Edition

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