Microsoft KB Archive/324916

= You receive an event warning when you use an Iomega Zip 250 drive to copy files to or from your Windows XP-based computer hard disk. =

Article ID: 324916

Article Last Modified on 11/10/2004

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Professional Edition

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This article was previously published under Q324916



SYMPTOMS
When you are using an Iomega Zip 250 drive to copy files to and from a hard disk on your Windows XP-based computer, you may receive the following Event warning in the System event log:

Event ID: 32

Description: The driver detected that the device \Device\Harddisk1\DR4 has its write cache enabled. Data corruption may occur.



CAUSE
The Iomega Zip 250 drive does not support requests by the operating system to turn off write caching. Because of this, an Event ID 32 warning is logged in the event log. This warning is by design. Event ID 34s are then incorrectly generated in the event log every time you start your computer, although they are supposed to be Event ID 32s.



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



MORE INFORMATION
The Iomega Zip 250 drive does not support the ForceUnitAccess bit, which the operating system uses to bypass all caching when it sends commands to the drive. Because of this, Windows tries to turn off write caching for the drive, and then retries the request. This request also fails because the Iomega drive write cache is always on. As a last attempt, Windows retries the request one more time without the ForceUnitAccess bit set.

As a result of the failed attempt to turn off write caching for the Iomega ZIP 250 drive, an Event ID 32 warning message is displayed in the event log. When the computer starts after this warning has been generated, Windows remembers that the drive does not support ForceUnitAccess. Windows then tries to turn off the disk cache, and this attempt fails. Windows lists these warnings as an Event ID 34 and not the appropriate Event ID 32.

Additional query words: fua

Keywords: kberrmsg kbbug kbenv kbpending KB324916

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