This article explains why Extend Volume option is disabled in Windows Server 2012 R2 Disk Management, and what to do if Extend Volume doesn't work.
Why Extend Volume is disabled for system C: drive
The most common issue in a server is that system partition C running out of space. It can't be better if you can expand it fast and without reinstalling OS and programs. To help extend a partition, Microsoft provides Extend Volume function in Disk Management tool, which is able to extend system partition and data volumes without losing data.
As we know, the size of a hard disk is fixed, so before extending a partition there must be Unallocated space. To get this space, you may either delete or shrink other partition. By shrinking a partition, only part of unused space will be converted to Unallocated and the files in it keep intact. Nobody likes to delete an allocated partition except have to.
There is indeed another Shrink Volume function in Server 2012 Disk Management, however, it can only make Unallocated space on the right side, which leads to Extend Volume doesn't work.
As you see in my server:
18.96GB Unallocated space is made on the right side of drive D: after shrinking.
Extend Volume is disabled for C: drive, because this function can only combine Unallocated space to the left contiguous partition. Drive C is nonadjacent, so it is not supported.
Some people try to delete partition D, then there is right contiguous Unallocated space, so Extend Volume is enabled for C drive. It indeed works in GPT disk, but in MBR style disk, it depends.
Do not delete drive D if you installed programs or any Windows services in it.
To show you the reason, I converted partition D from Primary to Logical.
After deleting D, the disk space is shown as Free instead of Unallocated. Extend Volume is still disabled for C: drive.
In MBR disk, Unallocated space deleted from a Primary partition cannot be extended to any Logical partition, Free space deleted from a Logical cannot be extended to any Primary partition. This is another serious restriction of Disk Management.
To convert the 70GB Free space to Unallocated, you have to delete another Logical partition E and then delete the entire Extended partition.
Why Extend Volume is disabled for D: or E:
To data volume D or E, the first reason is the same with system partition C - there is no right adjacent Unallocated space.
After shrinking drive C and E, there is 20GB Unallocated space behind C and 20GB Free space behind E.
Disk Management cannot shrink drive E to make Unallocated space on the left or combine Unallocated to the right adjacent partition. So, Extend Volume is disabled for D: drive.
If the partition type of E is different with drive D, you still cannot extend D drive by deleting E.
Another reason why Extend Volume option is disabled for D or E drive is because that this type of partition is not supported.
Both Shrink and Extend Volume functions only support the partitions that are formatted as NTFS or without file system (RAW). FAT32 and other types of partitions cannot be shrunk or extended.
To show you this restriction, I converted drive D to FAT32. As you see, Extend Volume is disabled, although there is 20GB Unallocated space next to it.
What to do when Extend Volume doesn't work
To solve these problem, it is very easy with NIUBI Partition Editor.
- You just need to drag and drop on the disk map to shrink and extend partition.
- Both NTFS and FAT32 partitions are supported.
- Unallocated space can be produced on either side when shrinking a partition.
- Unallocated space can be combined to either contiguous partition and moved to any nonadjacent volumes.
Download NIUBI Partition Editor and follow the step in the video to fix Windows Server 2012 Extend Volume option disabled issue:
Right click a partition and select "Resize/Move Volume" feature, drag the border towards the other side, then you can shrink this partition and make Unallocated space on either side, or extend this partition by merging Unallocated space on either side. Drag the middle position towards other side, then you can move this partition and associated Unallocated space.
With NIUBI Partition Editor, you can shrink partition and combine Unallocated space to any volume in the same disk, no matter the partition is NTFS or FAT32, Primary or Logical, on the left or right, adjacent or not.