Windows Server 2012 - Extend Volume Option Is Disabled In Disk Management


In this article, I will show How to extend the Operating System drive in Windows Server 2012?


When I tried to Extend Volume for a specific drive in Windows Server 2012 R2 by opening:
  • Server Manager > Computer Management.

Computer Management

  • Disk Management > Right Click on C:\ Drive.
  • Although I have an unallocated free space (about 19.5 GB). But unfortunately, the Extend Volume option is grayed out as shown below.

disk management extend Volume


The extend volume option is disabled because of there is no unallocated space beside directly the drive that you need to extend. and to be able to extend a specific drive volume you should make sure that there is no partition between the original partition and unallocated space as shown below
free space beside OS 


In this case, you will need to unallocated the drive space beside the operating system drive.(in my case it's F:\ ) but this means all data in this drive will be deleted! So, before we getting started you should Make sure that the unallocated space is at least equal to or greater than the used space in F:\ drive (the drive beside OS drive) to ensure that you can move the F:\ drive content to this space.


  • Create a new simple volume from the unallocated space.

disk management new Volume

  • Move the data files from F:\ Drive to the New Volume.
  • Delete F:\ Drive.

disk management delete Volume

  • You are now having unallocated space beside the Operating System drive.

free space beside OS

  • Again, try to extend the Operating System drive where the extend volume should be now enabled.

free space beside OS extend volume

  • The Extend volume wizard should be started > Next.

Extend Voulme Wizard.PNG

  • By default, all free space will be set, you can change the amount of space based on your requirement.

Set Space as required.PNG

  • Click finish, the OS Volume should be extended successfully.

Extend Voulme Wizard completed