Large Writes to Removable Media May Result in Data Loss

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Article ID: 239694 - View products that this article applies to.
This article was previously published under Q239694
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When a program attempts a large write to an ATAPI magneto-optical disk or an ATAPI Zip drive, the write process may not be completed and no error message may be returned to the program. This problem can potentially occur in programs that submit a single write request that is larger than approximately seven megabytes (MB).

You can identify this problem by using the File Compare (Fc.exe) utility to compare the source file with the destination file located on the removable media.

This problem does not occur with utility programs such as copying or using Windows Explorer to copy files, because these tools use multiple small buffers to copy a file.


This problem occurs because the input/output (IO) subsystem times out requests that take longer than 7.5 seconds and the large write process does not have enough time to finish.


A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:
Date Time Version Size File name Platform
08/03/99 03:02p 4.10.2184 24,430 Esdi_506.pdr Windows 98
08/12/99 09:03p 4.10.2223 24,430 Esdi_506.pdr Windows 98 
Second Edition


To work around this problem, use a smaller buffer when writing to removable media when you use WriteFile to write data to a file.


Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.


The Max Transfer Length setting for removable media has been decreased so that Windows breaks up large writes into smaller requests that do not exceed 7.5 seconds.

For additional information about Windows 98 and Windows 98 Second Edition hotfixes, click the article number below to view the article in the Microsoft Knowledge Base:
206071 General Information About Windows 98 and Windows 98 Second Edition Hotfixes


Article ID: 239694 - Last Review: January 25, 2007 - Revision: 2.1
  • Microsoft Windows 98 Standard Edition
  • Microsoft Windows 98 Second Edition
kbhotfixserver kbqfe kbdiskmemory kbhardware kbprb kbqfe KB239694

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