Cannot extend volume

Solution of Extend Volume Grayed out

This article explains why Extend Volume option grayed out in Disk Management and how to fix extend volume greyed out in Windows 10/8/7 and Server 2019/2016/2012/2008.

About Extend Volume functionality

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 some commands from DiskPart command prompt. It seems a bit difficult to some users, in addition, Unallocated space won’t be shown by DiskPart.

From Windows Vista, Microsoft added new GUI Shrink Volume and Extend Volume functionalities. Windows Server 2008 and all subsequent Operating System inherited these two functionalities. Over 10 years, the GUI and steps keep the the same.

As the name, Extend Volume is used to expand an existing partition drive without data loss, however, NOT every partition volume can be extended. The hard drives that fit for the requirement of Extend Volume can be extended fast and safely. But in fact, most of the partitions cannot be extended, because both Shrink and Extend Volume has some inherent limitations.

Many people feedback that Extend Volume greyed out in Disk Management. Search by Google and there are many similar complaints such as “Windows 10 won’t let me extend volume“, “extend volume is disabled for C drive“, “extend volume option is grayed out and doesn’t work“.

After reading this article, you’ll know why Extend Volume greyed out in Windows 10, 8, 7, Vista and Server 2019, 2016, 2012 and 2008 (R2).

Why Extend Volume greyed out in Disk Management

There are 4 common reasons that cause Extend Volume disabled and I’ll explain one by one.

Reason 1 No Unallocated space

Unallocated space is part of free disk space that is not used by any volume, it can be used to create new volume or combine into other drive via Extend Volume.

As we know, a 256GB hard disk drive cannot be increased to 512GB. Before extending a volume partition, there must be Unallocated space, otherwise, Extend Volume greyed out when you right click any drives in Disk Management.

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

  • After deleting a volume, all disk space will be converted to Unallocated, all files in it will be deleted, too.
  • After shrinking a volume, part of free space will be converted to Unallocated, all files are still there.

Reason 2 Unallocated space is nonadjacent or on the left side

In fact, only when there is adjacent Unallocated space on the right side of the drive that you want to extend, Extend Volume is valid. This is the most common scenario of Extend Volume greyed out that feedback by the Windows computer users.

As you see, 10GB Unallocated space is produced on the right side of D after shrinking, which is nonadjacent to drive C, so Extend Volume is grayed out when right clicking C drive.

If Shrink Volume has an option to produce Unallocated space on the left side of D, there won’t be such issue, but there’s no such option.

 Unsupported file system

Extend Volume option is only enabled for NTFS and RAW partition, any other types of partitions cannot be extended. From the screenshot below, Extend Volume greyed out for drive D, although there is right adjacent Unallocated space, because drive D is FAT32.

 Restriction of Extended partition

Tips This issue only exists on MBR style hard disk.

As I said above, there are two ways to get Unallocated space by deleting and shrinking. Because Shrink Volume cannot produce adjacent Unallocated space, some people try to delete this partition.


  • Remember to back up or transfer files before deleting.
  • Do NOT delete drive D if you installed programs in it.

If the adjacent drive D is a Primary partition, you’ll get adjacent Unallocated space for C drive in both MBR and GPT disk. But if D is a Logical partition, the disk space will be converted to Free space after deleting. As you see in the screenshot, Extend Volume still greyed out for C drive.

Extended partition works like a container and the Free space in it cannot be extended to any Primary partition. Meanwhile, Unallocated space deleted from a Primary partition cannot be extended into any Logical partition.

Tips All Logical partition can only be created in the Extended partition. All partitions created on GPT disk are Primary.

How to fix Extend Volume grayed out issue

It seems a bit complicated, but it is very easy to fix Extend Volume greyed out issue on both Windows Server and PCs. You just need NIUBI Partition Editor to drag and drop on the disk map to move and combine Unallocated space.

Typical example to fix Extend Volume greyed out issue:

Step 1 Download NIUBI Partition Editor, right click drive D and select “Resize/Move Volume”


Drag the middle position towards the other side in the pop-up window.

Move D

Click OK, Unallocated space is moved to the left side of D.

Unallocated moved

Step 2 Right click C drive and select “Resize/Move Volume” again, drag the right border rightwards in the pop-up window.

Extend C

Click OK, Unallocated space is combined to C drive.

System drive extended

If you want to merge the Unallocated space to drive E, right click E to run the Resize Volume feature and then drag the left border leftwards in the pop-up window.

Extend E

Tip NIUBI Partition Editor is designed to work in its virtual mode, to modify real disk partition, you need to click Apply to take effect. If you changed your mind, simply click Undo to cancel the pending operations.

In Summary

Because of the inherent limitations of both Shrink and Extend Volume, Extend Volume grayed out issue is very common in both Windows Server and PC. To fix these issue:

  1. When the Unallocated space is nonadjacent to the drive that you want to extend, move it adjacent on either side, and then combine to this drive.
  2. When the Unallocated space is adjacent on the either side, but Extend Volume greyed out because of not supported FAT32 partition or the restriction between Primary and Logical partition, simply drag the border towards other side to combine the Unallocated space.

Besides shrinking, moving and extending partition, NIUBI Partition Editor helps you do many other disk partition management operations. Better than other tools, it is integrated with unique 1 Second Rollback technology and Virtual Mode to ensure system & data intact. Thanks to its advanced file-moving algorithm, it is also much faster.