SIRIS, ALTO, and NAS: Windows 2008 - diskmgmt.msc displays "the disk is offline because of policy set by an administrator."



This article discusses the cause and solution of the error when virtualizing a machine: The disk is offline because of policy set by an administrator.


This error can happen due to the following:

  • Prior to the Virtual Machine's creation, the production machine's SAN policy set to being offline shared except for the boot disk.
    • This can be confirmed by opening a command prompt on the protected machine with admin privileges and using the following command:
      • diskpart.exe then select Enter.  This will show the SAN policy.


Please check out the following steps to troubleshoot the issue.  If this does not correct the problem, please contact Datto Technical Support for further assistance.


1. Open the command prompt on the protected machine.

2. Enter this command to change the SAN policy:

DISKPART> san policy=OnlineAll

This will shoot a message after saying if it has been successfully changed.

3. Now enter this command to list the current disk part:


Once done, select enter to display information regarding the disk, the number, status, size, and so forth.

4. Use the following command to select the proper disk:

DISKPART>; select disk 1

5. Use this command to ensure the disk is set to read only:


This will shoot a confirmation message

6. Now, have the diskpart list the attribute for confirmation with this command:

DISKPART> attributes disk

7. Confirm that the SAN policy has been successfully changed to online shared with this command:


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