Defragmentation Application Hangs

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Article ID: 191601 - View products that this article applies to.
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While running a defragmentation application on a volume that is formatted as FAT, the application can cease to respond (hang), along with other applications, and possibly the computer itself. No record of the hang will be logged. No entry will appear in the event logs, and a Dr. Watson error will not occur.


Running a defragmentation application while you actively open and close files forces Windows NT to enter a timing window. This timing window makes unsafe synchronization possible on the file being defragmented, and the system hangs as it waits for the error condition to be resolved. All defragmentation applications that use FSCTL_MOVE_FILE on FAT call are susceptible. This error is rare in occurrence.


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


Microsoft has confirmed that this is a problem in Windows NT 4.0. This problem was first corrected in Windows NT 4.0 Service Pack 4.


Article ID: 191601 - Last Review: October 10, 2013 - Revision: 1.1
  • Microsoft Windows NT Server 4.0 Standard Edition
  • Microsoft Windows NT Workstation 4.0 Developer Edition
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