Why Extend Volume is disabled and how to fix

by James, Updated on: October 14, 2020

This article explains why Extend Volume option is disabled in Windows Disk Management, and what to do when Extend Volume is disabled for C drive or a data partition.

Applies to: Windows 10, Windows 8/8.1, Windows 7, Windows Vista, Windows Server 2019, Windows Server 2012 R2, Windows Server 2008 R2, Windows Small Business Server (SBS) 2011/2008.

Extend Volume option is disabled in Disk Management

Most of Windows computer users encountered the low disk space issue on system C drive. Windows Updates, programs and many other types of files write into C drive every day, so it becomes full sooner or later. If it happens in Windows XP or Windows Server 2003, you have to back up everything, delete and recreate partitions, finally restore. Maybe Microsoft found this defect, so it added new Shrink and Extend volume functions in native Disk Management from Windows 7 and Server 2008. It is a good start but most of disk space issue still cannot be fixed.

When C drive is running out of space, it cannot be better if you can extend C drive without losing data, right? Unfortunately, after shrinking D or other volume Extend Volume option is disabled for C drive. In this article, I'll explain all probable reasons and what to do when Extend Volume is disabled in Disk Management of Windows laptop, desktop and server.

Reasons why Extend Volume is disabled for system C drive

Reason 1: No required Unallocated space

A 300GB hard disk cannot be increased to 500GB (except VMware/Hyper-V virtual disk), so before extending a partition you must delete or shrink another one to get some Unallocated space. As the name, this space is not allocated to any drive. In Windows XP and Server 2003 Disk Management, Unallocated space can only be used to create new volume. In Windows 7 and subsequent versions, it can be added to other partition and converted to free space.

To get Unallocated space, you may either delete or shrink a partition. After deleting a volume, all its disk space will be converted to Unallocated but you'll lose all files in it. By shrinking a volume, only part of free space will be converted to Unallocated and you won't lose files in it.

Obviously, it's better to get Unallocated space by shrinking a volume. The problem is that you can't extend C drive after shrinking D or any other volume with Disk Management. As the screen shot shows, Extend Volume is disabled for C: and E: drive after shrinking D.

Extend Volume disabled

This is because:

  • Shrink Volume function can only make Unallocated space on the right while shrinking any partition.
  • Extend Volume function can only combine Unallocated space to the contiguous partition on the left.

The Unallocated space that shrunk from D is non adjacent to C drive and is on the left of E drive, therefore, Extend Volume option is disabled in Disk Management.

Reason 2: Different partition type

Extend Volume function only works when there's contiguous Unallocated space on the right side. As I explained above, you can't get such required Unallocated space by shrinking a partition. Is it possible to enable Extend Volume by deleting the contiguous partition on the right? The answer is yes if this disk is GPT. If you use MBR disk, it depends. If the right contiguous partition D is Logical drive, you still cannot extend C drive in Disk Management after deleting D.

Extend volume disabled

As you see in the screenshot, Extend Volume is disabled for C drive after deleting D.

This is because:

In MBR style hard disk, Free space deleted from a Logical partition can't be extended to any Primary partition. Unallocated space deleted from Primary partition can't be extended to any Logical drives.

Therefore, in MBR disk, the partitions that you want to delete and extend must be the same Primary partition or Logical drive.

In MBR disk there are only 4 entries in Master Boot Record sector, so you can only create 4 Primary partitions or 3 Primary plus an Extended partition. Unlike Primary partition that works as independent unit, Logical drives are part of the Extended partition, this is the reason why it is shown as Free after deleting.

Why Extend Volume is disabled for D or other data volume

Reason 3: File System is not supported

Extend Volume function only support extending NTFS partition, it cannot extend FAT32 or any other types of partition even if there is adjacent Unallocated space on the right side.

Extend Volume disabled

As you see in the screenshot, there's 20GB Unallocated space next to D: drive, but because it is a FAT32 partition, so Extend Volume is disabled.

In most of Windows computers, system C drive is formatted with NTFS, so this issue is just common for data drives.

Reason 4: 2TB limitation of MBR disk

Nowadays, hard disks are much larger and it is very common to use 2TB to 4TB disk for personal computers. To a server, it is common to use over 10TB RAID array via several large disks. The problem is, if you initialized a 4TB disk as MBR, you can only use 2TB disk space. The maximum partition size is also 2TB on a MBR disk.

Extend Volume grayed

As the screen shot shows, drive H is formatted as NTFS and there is right contiguous Unallocated space, but Extend Volume is still disabled. If you right click this Unallocated space in Disk Management, all options are unavailable.

To solve this problem, you need to convert disk from MBR to GPT and then extend partition with Unallocated space.

What to do when Extend Volume is disabled in Windows Server & PC

Download NIUBI Partition Editor, you'll see all disks (physical and RAID virtual) with partition structure, follow the corresponding solution according to your own disk partition configuration.

Solution 1: Move Unallocated space

When Extend Volume is disabled for C drive after shrinking D or other volume, move Unallocated space to the left and then add to C drive, follow the steps below:

  1. Run NIUBI Partition Editor, right click drive D and select "Resize/Move Volume", drag the middle towards right in the pop-up window.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine Unallocated space.
  3. Click Apply on top left to execute.

Video guide

Solution 2: Merge adjacent Unallocated space

When there's adjacent Unallocated space, Extend Volume is disabled because of non-supported FAT32 partition or the restriction between Primary and Logical partition, follow the steps below:

  1. Run NIUBI Partition Editor, right click the adjacent partition and select "Resize/Move Volume".
  2. Drag the border towards other side to combine Unallocated space in the pop-up window.
  3. Click Apply on top left to execute.

Video guide

Solution 3: Convert 2TB+ MBR disk to GPT

When Extend Volume option is disabled on a larger than 2TB disk, follow the steps below:

  1. Run NIUBI Partition Editor, right click front of this disk and select "Convert to GPT Disk".
  2. Run "Resize/Move Volume" function and combine Unallocated space to the partition(s) that you want to expand.

Video guide

Better than other tools, NIUBI Partition Editor has innovative technologies to protect system and data such as:

It is 30% to 300% faster because of the advanced file-moving algorithm, it's very useful when you move partition with large amount of files.

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