Reactivate a missing or offline dynamic disk

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

To reactivate a missing or offline dynamic disk

Open Computer Management (Local).
In the console tree, click Computer Management (Local), click Storage, and then click Disk Management.
Right-click the disk marked Missing or Offline, and then click Reactivate Disk.

The disk should be marked Online after the disk is reactivated.

Notes

To perform this procedure on a local computer, you must be a member of the Backup Operators group or Administrators group on the local computer, or you must have been delegated the appropriate authority. To perform this procedure remotely, you must be a member of the Backup Operators group or Administrators group on the remote computer. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure. For more information, see Default local groups, Default groups, and Using Run as.
To open Computer Management, click Start, click Control Panel, double-click Administrative Tools, and then double-click Computer Management.
A dynamic disk may become Missing when it is corrupted, powered down, or disconnected.
A dynamic disk may become Offline if it is corrupted or intermittently unavailable. A dynamic disk may also become Offline if you attempt to import a foreign (dynamic) disk and the import fails. An error icon appears on the Offline disk. Only dynamic disks display the Missing or Offline status.
Only dynamic disks can be reactivated.

Open Command Prompt.
Type:

diskpart
At the DISKPART prompt, type:

list disk

Make note of the disk number of the missing or offline disk that you want to bring online. Missing disks are numbered M0, M1, M2, etc. and offline disks are numbered 0, 1, 2, etc.
At the DISKPART prompt, type:

select diskn
At the DISKPART prompt, type:

online

Value	Description
list disk	Displays a list of disks and information about them, such as their size, amount of available free space, whether the disk is a basic or dynamic disk, and whether the disk uses the master boot record (MBR) or GUID partition table (GPT) partition style. The disk marked with an asterisk (*) has focus.
select diskn	Sets the focus to the specified disk, where n is the disk number.
online	Brings an offline disk or volume with focus online.

Notes

To perform this procedure on a local computer, you must be a member of the Backup Operators group, Administrators group, or you must have been delegated the appropriate authority. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure. For more information, see Default local groups, Default groups, and Using Run as.
To open a command prompt, click Start, point to All programs, point to Accessories, and then click Command prompt.
A dynamic disk may become Missing when it is corrupted, powered down, or disconnected.
A dynamic disk may become Offline if it is corrupted or intermittently unavailable. A dynamic disk may also become Offline if you attempt to import a foreign (dynamic) disk and the import fails. Only dynamic disks display the Offline status.
Only dynamic disks can be reactivated.
For more information about DiskPart, see Related Topics.

Your server might function differently based on the version and edition of the operating system that is installed, your account permissions, and your menu settings. For more information, see Viewing Help on the Web.