This error occurs when the Storage Area Network (SAN) policy that applies to the computer is set to server. A SAN enables a server to mount disks and other storage devices automatically from other computers. By configuring the SAN policy on a Windows computer, it can be specified which disks can be automatically mounted, and specify to disable disks from being mounted automatically. If the SAN policy value is set to 2 (VDS_SP_OFFLINE_SHARED) whenever a new disk is detected, it goes offline as specified by the policy.

In any of the following scenarios, bring the disk online manually:

Scenario 1

If the operating system restarts successfully after the SDR restore, then use the Windows Disk Management tool or the DiskPart command line utility to bring the disk online.

Scenario 2

If the operating system cannot restart successfully after the SDR restore, then you can restart the computer in safe mode or if Active Directory is present, in Directory Services Restore Mode (DSRM). Then, use the Disk Management tool or the DiskPart command line utility to bring other disks online.

Scenario 3

If the operating system cannot restart using any boot mode, use the following steps:

1. Boot the operating system into SDR mode.
2. Open the registry editor.
3. From File>Load HIVE, load the System HIV of the target system which is in the target system's folder at C:\Windows\System32\config.
4. Change the registry value of the following key to 1:

Target_system_HIV\ControlSet001\services\partmgr\Parameters\SANPolicy REG_DWORD = 1

This change brings all available disks online. After you boot into the restored operating system, you must use the Disk Management tool to take any required disks offline manually.

For more information on SAN Policy, refer to the Microsoft article at the following link:

http://technet.microsoft.com/en-us/library/ff715663.aspx

Another more detailed blog on SAN Policy is available at the following link:

http://blogs.technet.com/b/system_center_configuration_manager_operating_system_deployment_support_blog/archive/2012/01/23/when-deploying-windows-server-2008-using-an-configuration-manager-osd-task-sequence-additional-disks-may-show-as-offline-when-the-task-sequence-completes.aspx

For more information on bringing disks online, follow the link http://technet.microsoft.com/en-us/library/dd163558.aspx and search in the section 'Setting a Disk Online'.