When certain programs are used to edit or transfer files that are stored on a Windows Home Server-based computer that has more than one hard drive, the files may become corrupted. Microsoft is aware of only a very small percentage of users who have confirmed instances of this issue and believes that most users are unlikely to be affected. Microsoft has established that this issue may occur when one of the following programs is used to edit, transfer, and save files to the home server:

•	Windows Vista Photo Gallery
•	Windows Live Photo Gallery
•	Microsoft Office OneNote 2007
•	Microsoft Office OneNote 2003
•	Microsoft Office Outlook 2007
•	Microsoft Money 2007
•	SyncToy 2.0 Beta
•	Intuit QuickBooks
•	uTorrent

Note Windows Home Server-based computers that have a single hard drive are not affected by this issue, nor are Windows Home Server Computer Backup and Restore capabilities, Health Monitoring, and Remote Access functionality. This issue is specific to Windows Home Server and does not affect other Windows Server-based products.

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A bug has been discovered in the way that Windows Home Server manages file transfer and balancing across multiple hard drives. In certain cases, depending on application use patterns, timing, and the workload that is placed on the Windows Home Server-based computer, certain files may become corrupted. For additional technical details about the cause of this issue see the “CAUSE – TECHNICAL DETAILS” section later in this article.

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This issue can now be reliably reproduced, and a fix is in development. Microsoft intends to release beta test versions of a fix over the next few months, with a final version currently planned for June 2008. That date could change as testing progresses. Thorough testing of the fix is critical and will take time.

Until a software fix for Windows Home Server is available, users may choose to act to help limit the possibility of being affected by this issue. As a precautionary measure, users should use Windows Explorer or a command-line tool to copy files to and from the Windows Home Server-based computer. Do not use applications to directly edit or change files that are stored on the Windows Home Server-based computer.

Users may consider setting Shared Folders on Windows Home Server to read-only and avoid using media management programs, such as Windows Media Player, to import files to the home server. They may also want to avoid redirecting applications to access files that are stored in the Shared Folders because some applications may change the metadata of a file without explicit user action.

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CAUSE – TECHNICAL DETAILS

Windows Home Server uses a file system mini-filter driver in addition to the NTFS file system to implement Shared Folders storage technology. File system mini-filter drivers are an extensibility mechanism that is provided by Windows to enable storage scenarios. For distributing data across the different hard drives that are managed by Windows Home Server, the Windows Home Server mini-filter driver redirects I/O between files that are stored on the main hard drive and files that are stored on other hard drives. This redirection mechanism is enabled only when Windows Home Server is managing the Shared Folder storage of multiple physical hard drives. A bug has been discovered in the redirection mechanism which, in certain cases, depending on application use patterns, timing, and workload, may cause interactions between NTFS, the Memory Manager, and the Cache Manager to get out of sync. This causes corrupted data to be written to files. More information about the storage technology can be found in the following technical brief:

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OTHER PROGRAMS

Users have reported potential corruption issues when they use other programs to edit or transfer files that are stored on Windows Home Server-based computer that has more than one hard drive. For more information, see the following list. Microsoft is in the process of trying to reproduce the issues and directly assess the causes. The nature of the issues precludes Microsoft from providing a definitive list of affected applications. If users believe they have evidence that they are experiencing the issue, please send a detailed e-mail of their circumstances to whsforum@microsoft.com so that Microsoft can try to validate the cause and provide specific guidance.

•	Photoshop Elements
•	Zune Software
•	Apple iTunes
•	TagScanner
•	Mozilla Thunderbird
•	Adobe Lightroom
•	Intuit Quicken
•	MS Digital Image Library
•	MP3BookHelper
•	ACDSee
•	WinAmp
•	Windows Media Player 11
•	Microsoft Office Excel
•	Visual DataFlex

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The following table lists significant technical revisions to this article.

Date	Revisions
December 21, 2007	Original publication date
December 28, 2007	Updated the article to document more information about the scenario in which this issue occurs
January 9, 2008	Updated the article to indicate that Microsoft can reproduce the issue and is currently working on a fix
February 20, 2008	Changed the original publication date to the correct date. Updated the list of applications in the Symptoms section. Provided an updated status.
March 6, 2008	Provided updated information about symptoms, cause, status and guidance.

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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