This article introduces why cannot extend volume in Windows Server 2008 R2 Disk Management or via diskpart, and what to do if unable to extend partition.
Why can't extend volume in Server 2008 Disk Management
Better than previous Windows Server 2003, Server 2008 native Disk Management provides new Shrink Volume and Extend Volume to change partition size without losing data. When server runs out of space, it can't be better if you can extend disk partition without wasting a long time to recreate partitions and restore from backup. However, many people feedback that they cannot extend volume in Server 2008 Disk Management, because Extend Volume option is disabled.
There are several reasons why can't extend volume in Windows Server 2008 Disk Management.
1. No right adjacent Unallocated space
The size of a disk is fixed, a 500GB disk can't be decreased to 250GB or increased to 1TB. Therefore, before extending a hard drive partition, there must be free Unallocated space.
Although there is Shrink Volume function to decrease partition, it can only make Unallocated space on the right. This space can't be extended to the right contiguous or any nonadjacent partitions with Extend Volume function.
As you see in the screenshot, the 20GB Unallocated space is shrunk from drive D, Disk Management cannot extend volume C: and E: with this space.
If you want to extend partition C with Server 2008 Disk Management, you must delete the adjacent drive D. If there is no or you cannot delete the right contiguous partition, Disk Management is completely useless.
2. File system not supported
From Microsoft explanation, Extend Volume can only expand the partitions that are formatted with NTFS or without file system (RAW).
As you see in the screenshot, drive D is FAT32, both Shrink and Extend Volume are grayed out, although there is adjacent Unallocated space on the right.
3. Different partition type
Cannot get adjacent Unallocated space by shrinking volume, some people wonder if it is possible to delete the right adjacent partition to enable Extend Volume. It works in GPT disk, but in MBR disk you cannot extend a partition with the space from other partition whose type is different.
For example, if both C and D drive are Primary partition, it works by deleting D. But if drive D is Logical, Extend Volume is still disabled for C drive after deleting it.
In Server 2008 Disk Management, Unallocated space deleted from Primary partition can't be extended to any Logical partition. Free space deleted from Logical partition can't be extended to any Primary partition.
Free space is still part of the Extended partition, to convert it to Unallocated, you have to delete all other Logical and the entire Extended partition.
Why cannot extend volume via diskpart command
Diskpart works via command prompt, but it has similar restrictions with Disk Management.
- The partition that you want to expand must be formatted as NTFS or without file system (RAW).
- The free (Unallocated) space must be adjacent and on the right side of the partition that you want to expand.
- Free (Unallocated) space and the partition must be on the same disk.
Better than Disk Management, diskpart can extend C drive by deleting D even if D is Logical partition.
What to do when unable to extend volume
To most of servers, the reason why cannot extend volume in Server 2008 Disk Management or via diskpart is because no right adjacent Unallocated space. To solve this problem, you just need to run NIUBI Partition Editor and move Unallocated space next to C drive.
Download NIUBI Partition Editor and you'll see the main window with disk partition structure and other information.
Solution when cannot extend volume/partition in Windows Server 2008 R2:
Step 1: Right click the right adjacent partition (D:) and select "Resize/Move Volume", drag middle position towards right in the pop-up window.
Step 2: Right click C: drive and select "Resize/Move Volume" again, drag right border towards right in the pop-up window.
Step 3: Click Apply on top left to execute.
If you have not got Unallocated space, you can shrink the contiguous partition (D:) and make Unallocated space on the left directly. If you cannot extend partition because this partition is FAT32, or the Free/Unallocated space is deleted from a different type of partition, you can combine directly with NIUBI.
Better than other tools, NIUBI Partition Editor has unique 1 Second Rollback, Virtual Mode, Cancel-at-well technologies and advanced moving algorithm to help repartition hard drive safely and fast. It also helps do many other disk partition operations.