This page details how to correct the “Disk is offline due to an administrator policy” error that occurs in Windows Server 2008 and Windows Server 2012. You’ll see this error under Disk Management if you hover your mouse over the little “i” icon. Note that you’ll also get this error if you’ve just installed a virtual machine (VM) with Windows 2008 Enterprise or Datacenter, or if you’ve upgraded the virtual machine to Virtual Hardware 7.

The reason for this error is that all virtual machine disk files (VMDK) are presented to virtual machines as SAN disks. On Windows Server 2008 Enterprise, Windows Server 2008 Datacenter and later versions (e.g. newer versions such as 2012), the default SAN policy is now VDS_SP_OFFLINE_SHARED for all SAN disks, with the exception of the boot disk. If you’re new to all this, we’re going to have a bit of storage networking. Typically, a person will install 2 RAID arrays on a server, install the operating system on one array (such as Windows Server 2012), then boot into that operating system. Once there, he’ll find he can’t be seen because it’s easy to get started.

If the rule is set to “Shared offline”, you’ll find that the SAN disks (RAID arrays) will be offline when your operating system boots up. Fortunately, the problem is easily solved with a few simple commands in the Windows cmd interface. Let’s start by taking a look at the current SAN policy from the command line:

Type

diskpart

This changes your prompt and enters diskpart mode. Now type

SAN

This shows :

SAN Policy : Offline Shared

If you see this, then all is well. Now we need to make a change to the SAN policy so that all virtual machines can see the disk. Still in DISKPART mode, enter:

san policy=OnlineAll

Now let’s take a look at the discs :

LIST DISK

Choose the disk you can’t see in Windows (CAREFULLY!). Now type

select disk 1

where disk 1 is your offline disk. Again, check this !

It should now say “Disk 1 is now the selected disk.”

Now let’s clear the attributes with :

ATTRIBUTES DISK CLEAR READONLY

attributes disk

Cela retournera probablement quelque chose comme:

Current Read-only State : No
Read-only : No
Boot Disk : No
Pagefile Disk : No
Hibernation File Disk : No
Crashdump Disk : No
Clustered Disk : No

This will probably return something like :

ONLINE DISK

Now, right-click on the boot icon (Windows Server 2012 etc) and go to Computer Management then Disk Management. You should see the “Initialize disk” dialog box. Select “MBR” instead of “GPT” if you want older versions of Windows to use this disk.

Restart the server and we should now see your drive / array from Windows !