Article ID: 937251 - View products that this article applies to.
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Consider the following scenario:
Note You may experience this problem if you configure the operating system during installation or if you perform a recovery process that was provided by the computer manufacturer. This problem can also occur during regular operating system startup. Therefore, hard disks may have different disk numbers across multiple system startups. Also, drives may enumerate in different orders if the operating mode of the hard disk controller is changed in the BIOS (for example, RAID mode versus non-RAID mode).
The disk-assignment numbers may not necessarily match the corresponding SATA or RAID channel numbers. There is no assurance of a consistent relationship between PnP enumeration and the order of the hard disks that are detected during startup. Devices are presented in the order in which they are enumerated. Therefore, the disk assignment numbers may change between startups. For example, assume that you run Windows or Windows Server Setup on a computer that has two unformatted SATA or RAID hard disks. In this situation, Windows may present the second hard disk as Disk 0 when you are prompted for the disk on which to install the operating system.
When you set up any of the operating systems that are listed in the "Symptoms" section on a computer that has multiple SATA or RAID hard disks, verify the disk drive on which you will set up the system by checking the disk information. For example, on the screen that lets you select the drive for the setup destination, verify the volume name and the available space.
To see the assigned disk numbers, use any of the following methods:
When you set up one of the operating systems that are listed in the "Symptoms" section on a computer that has multiple hard disks, you expect the disk assignment numbers to match the corresponding SATA or RAID channel numbers. If you experience mismatched channel assignments, you may set up the operating system on the wrong drive, or you may try to format the incorrect drive partition. Therefore, you may lose important data.
Additionally, when you install Windows Server 2012, Windows Server 2008 R2, Windows 8, or Windows 7, the installation creates a system partition alongside the Windows partition by default. The system partition is created to accommodate a Bitlocker requirement. Bitlocker requires that the boot files and Windows files are located on separate partitions. If the preselected default hard disk is not changed, the system partition is created on the disk that is detected as Disk 0.
Microsoft has confirmed that this problem is due to design limitations in the Microsoft products that are listed in the "Applies to" section. This problem occurs because drives are enumerated in the order in which they are presented to the operation system by the system BIOS.
For more information about a related issue, click the following article number to view the article in the Microsoft Knowledge Base:
937252For more information about PnP enumeration and hard disk drive letter assignments in Windows Server 2003 and Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/937252/ )Volume numbers in the "Volume ###" column may change every time that you run the "List Volume" command in the Diskpart.exe utility in Windows
(http://support.microsoft.com/kb/825668/ )Overview of PNP enumeration and hard disk drive letter assignments in Windows Server 2003 and Windows XP
Article ID: 937251 - Last Review: February 15, 2013 - Revision: 6.0