This article was previously published under Q191601
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While running a defragmentation application on a volume that is formattedas FAT, the application can cease to respond (hang), along with otherapplications, and possibly the computer itself. No record of the hang willbe logged. No entry will appear in the event logs, and a Dr. Watson errorwill not occur.
Running a defragmentation application while you actively open and closefiles forces Windows NT to enter a timing window. This timing window makesunsafe synchronization possible on the file being defragmented, and thesystem hangs as it waits for the error condition to be resolved. Alldefragmentation applications that use FSCTL_MOVE_FILE on FAT call aresusceptible. 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 theMicrosoft 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.