The same with other versions, Windows Server 2012 has native Disk Management tool to help manage server storage device. With this native tool, you can create, delete, format volume and change drive letter. Besides the basic disk partition management ability, it can help you change partition size with advanced "Shrink Volume" and "Extend Volume" functions. Extend Volume can extend system partition and data volumes without losing data (in most cases). However, it only works under restricted condition. Many people feedback that Extend Volume greyed out in Server 2012 (R2) Disk Management but they don't know the reason. In this article, I'll introduce why Extend Volume is disabled in Windows Server 2012 (R2) and how to fix this issue easily.
Why Extend Volume is disabled in Server 2012 Disk Management
There are 6 reasons why Extend Volume greyed out in Windows Server 2012 (R2) Disk Management, I'll show you one by one.
Reason 1: No Unallocated space
The size of a physical disk is fixed. Before extending a partition, there must be "Unallocated" space. A 500GB disk can't be decreased to 400GB or increased to 600GB. You can resize a partition, but you can't resize a disk (except virtual disk).
If you right click a volume without Unallocated space, of course Extend Volume is grayed out in Server 2012 Disk Management. To get Unallocated space, you may either delete or shrink an existing partition.
Reason 2: Unallocated space is nonadjacent
This is the most common reason why Extend Volume greyed out in Server 2012 r2 Disk Management.
"Shrink Volume" function can only make Unallocated space on the right while shrinking a partition, but this Unallocated space can't be merged to other partition with Disk Management. Because "Extend Volume" function can only extend Unallocated space to the contiguous partition on the left.
As you see in the screenshot, Extend Volume is disabled for C: and E: after shrinking D: drive. Because the Unallocated space that shrunk from D is nonadjacent to C drive and is on the left of E drive.
Reason 3: File System is not supported
From Microsoft explanation, Extend Volume function only support expanding the partitions that are formatted with NTFS or without file system (RAW).
If this partition is FAT32 or any other types, Extend Volume option is grayed out even if there is adjacent Unallocated space on the right.
Reason 4: Free space can't be extended to Primary partition
In most of servers, system partition C is NTFS and Primary. If the right contiguous volume D is a Logical drive, you still cannot extend C: drive even after deleting D.
After deleting a Logical drive, its disk space will be changed to "Free". Free space is still part of the Extended partition. To convert it to Unallocated, you must delete all other Logical drive and the entire Extended partition.
As you see in the screenshot, after deleting Logical drive D, the disk space is Free and Extend Volume is disabled for C drive.
Reason 5: Unallocated space can't be extended to Logical partition
Similarly, Unallocated space that deleted from a Primary partition cannot be extended to any Logical drive with Disk Management.
Reason 6: 2TB limitation on MBR disk
If you initialized a 2TB+ disk as MBR, you can use only 2TB space, the remaining disk space is Unallocated but it can't be used to create new volume or added to other volume in Disk Management. When you right click this Unallocated space, all options are grayed out.
As the screenshot shows, F: drive is formatted with NTFS and there is right contiguous Unallocated space, but Extend Volume option is grayed out in Server 2012 Disk Management.
How to fix Extend Volume greyed out in Windows Server 2012 (R2)
If you have got Unallocated space by shrinking the adjacent D drive, you need to move partition D to the right and make Unallocated space contiguous to C drive, then Extend Volume will be enabled.
Download NIUBI Partition Editor and you'll see the main window with disk partition structure and other information. There is 20GB Unallocated space that is shrunk from D drive with Disk Management.
How to fix "Extend Volume" greyed out in Server 2012 R2 by moving partition:
Step 1: Right click D: drive and select "Resize/Move Volume", put mouse pointer in the middle of D drive and drag it towards right in the pop-up window:
Step 2: Right click C: and select "Resize/Move Volume" again, drag right border towards right in the pop-up window.
Step 3: Click Apply on top left to take effect to real disk partition. (The operations before clicking Apply just work in virtual mode.)
When there is contiguous Unallocated space on either left or right of the partition that you want to extend, you can combine it with NIUBI Partition Editor by 1 step, no matter this partition is NTFS or FAT32, Logical or Primary partition. If Unallocated space is nonadjacent, you can move it and then combine to partition.
Watch the video how to fix Windows Server 2012 Extend Volume greyed out issue:
If Extend Volume greyed out for a 2TB partition on MBR disk, follow the steps in the video to convert MBR to GPT and then extend partition with Unallocated space.
When Extend Volume is grayed out in Server 2012 (R2) Disk Management, find out the associated reason on your server and follow the corresponding method above. Besides shrinking, moving and extending partition, NIUBI Partition Editor helps you merge, copy, convert, hide, wipe, defrag, scan partition and much more.