Why Extend Volume greyed out and how to fix

By Andy, Updated on: October 15, 2020

This article explains the reasons why Extend Volume is grayed out in Windows Disk Management and how to fix extend volume greyed out issue on Windows PC and Server.

Applies to: Windows 10, Windows 8, Windows 7, Windows Vista, Windows Server 2019, Windows Server 2016, Windows Server 2012 (R2), Small Business Server 2011, Windows Server 2008 (R2).

About Windows Extend Volume function

In old Windows XP and Server 2003, you can only do some basic operations in Disk Management such as create, delete and format partition. To change size of allocated partition, you need to run DiskPart command prompt. It is a bit difficult to most of personal computer users, thus, from Windows 7, Microsoft added new Shrink Volume and Extend Volume functions with graphical interface. Windows Server 2008 and all subsequent versions inherited the same functions without any improvement.

As the name, Extend Volume is used to expand allocated partition without data loss, however, because of many limitations of this function, most of partitions can't be extended. Many people feedback that Extend Volume greyed out in Disk Management. Searching by Google and you'll see many similar complaints such as "Windows 10 won't let me extend volume", "extend volume is disabled for my C drive", "extend volume option is grayed out and doesn't work in my computer".

In this article, I'll introduce all probable reasons why Extend Volume option is grayed out and the corresponding solutions.

Why extend volume is grayed out in Windows PC & Server

There are 5 common reasons that why Extend Volume greyed out in Windows Disk Management and I'll explain one by one.

Reason 1: No Unallocated space

Unallocated is part of disk space that is not belong to any volume, it can be used to create new volume or extend other partition. As we know, a 256GB physical hard disk drive can't be decreased to 200GB or increased to 300GB. Therefore, before extending a partition, there must be Unallocated space on the same disk, otherwise, Extend Volume will be grayed out when you right click any drive in Disk Management.

There are 2 ways to get Unallocated space: delete and shrink a volume.

  1. After deleting a volume, all disk space will be converted to Unallocated, all files in it will be deleted, too.
  2. After shrinking a volume, part of free space will be converted to Unallocated, all files keep intact.

Reason 2: Unallocated space is nonadjacent or on the left side

This is the most common reason why Extend Volume greyed out on both Windows Server and PC.

When shrinking a volume, the only option in Disk Management is entering an amount of space. You cannot choose to make Unallocated space on the left or right side of this partition. It is not an issue if you just want to decrease a partition to create new, but if you want to extend a partition by shrinking another one, it is impossible in Disk Management, because Extend Volume only works when there's contiguous Unallocated space on the right.

Extend Volume greyed out

As you see in the screenshot of my test computer, there is 20GB Unallocated space generated after shrinking my D drive.

The only way to enable Extend Volume for drive C is by deleting the adjacent drive D. But to drive E, there is no way in Disk Management.

Do not delete drive D if you installed programs in it, and remember to transfer files first if you can delete it.

Reason 3: Unsupported file system

Both Shrink and Extend Volume functions only support the partitions that are formatted with NTFS file system. Thus, if you right click FAT32 or any other types of partitions, Extend Volume option is grayed out.

In my test computer, there is 59.46GB Unallocated space that is adjacent and on the right side, but drive D is FAT32, so Extend Volume doesn't work.

Can't extend partition

Reason 4: Restriction between Primary and Logical partition

In GPT style disk, all partitions are created as Primary, but in MBR disk, there could be both Primary and Logical partition. Unlike Primary partitions that work as independent unit, Logical Partition is part of the Extended partition. Extended partition works like a container and the disk space of Logical drive will be converted to Free instead of Unallocated after deleting.

In Disk Management, free space deleted from Logical drive can't be extended to any Primary partition, Unallocated space deleted from Primary partition can't be extended to any Logical drive.

Extend Volume disabled

Logical drive

Reason 5: 2TB limitation in MBR disk

Nowadays, hard disks are much larger and it is common to use 2TB+ disk for personal computers. To a server, it is common to use over 10TB RAID array via several large disks. But if you initialized the disk as MBR, you can use only 2TB space, the remaining space can't be created new or added to other volume in Disk Management. When you right click the Unallocated space in Disk Management, all options are grayed out.

As the screen shot shows, drive H is formatted with NTFS and there is right contiguous Unallocated space, but Extend Volume still greyed out.

Extend Volume grayed

What to do when extend volume greyed out in Disk Management

Solution 1: Shrink and extend partition with NIUBI

If there's no Unallocated space, Download NIUBI Partition Editor and follow the steps in the video to shrink D or other volume, and then add Unallocated space to C drive.

Video guide

Solution 2: Move Unallocated space to the left

If you've shrunk D or other volume to get Unallocated space, follow the steps in the video to move Unallocated space to the left and then add to C drive.

Video guide

Solution 3: Merge contiguous Unallocated space

If there's contiguous Unallocated space on either side of the partition that you want to extend, simply merge Unallocated space to this partition with NIUBI, no matter you want to extend NTFS/FAT32, Primary/Logical partition. Follow the method in the video:

Video guide

Solution 4: Convert MBR disk to GPT

If Extend Volume greyed out because of 2TB limitation in MBR disk, follow the steps in the video to convert MBR disk to GPT and then extend partition with Unallocated space.

Video guide

Besides help fix extend volume greyed out issue in Windows 10/8/7 and Server 2019/2016/2012/2008, NIUBI Partition Editor helps you do many other operations such as merge, copy, defrag, hide, wipe, convert, create, format, scan bad sectors, etc.