Microsoft KB Archive/294776

= EFI Partition Is Not Available in Windows Explorer After You Mount It =

Article ID: 294776

Article Last Modified on 12/1/2007

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APPLIES TO


 * Microsoft Windows XP Professional x64 Edition
 * Microsoft Windows Advanced Server, Limited Edition

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This article was previously published under Q294776





SYMPTOMS
After you use the MOUNTVOL utility to mount your Extensible Firmware Interface (EFI) partition, you are unable to see the new drive letter in Microsoft Windows Explorer or My Computer.



CAUSE
This behavior occurs because with GUID Partition Table (GPT) disks, the EFI partition does not have a volume ID or volume name. Windows Explorer and My Computer use the volume name to identify the drive.



RESOLUTION
After you mount the EFI partition, you can access the drive letter through the command prompt without issue. This is currently the only way to access the partition without third-party products.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section of this article. 

MORE INFORMATION
For additional information about this issue, click the following article number to view the article in the Microsoft Knowledge Base:

294773 HOW TO: Access an EFI Partition in Windows XP 64-Bit Edition

Additional query words: IA64 64-bit EFI

Keywords: kbhardware kbnofix kbprb kbui KB294776

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