Extend volume grayed out

How to fix extend C drive greyed out in Disk Management?

If you find that Extend Volume for C drive is grayed out or disabled in Disk Management of Windows 10/8/7/Vista, then this article will help you. It explains why extend C: drive greyed out and how to solve this problem fast and easily. Windows built-in Extend Volume functionality helps you extend system C drive and any data volumes fast and safely, however, because of many limitations you still need third party software in most situations. In this article, I’ll show you the easiest solution and detailed steps with free partition software.

Extend volume grayed out

Extend C drive grayed out

Remember one rule: only when there is adjacent Unallocated space on the right side, you can expand a drive with Extend Volume functionality.

So if you right click C: drive directly, Extend Volume is grayed out.

Extend C drive grayed out

If you shrank the contiguous drive D with Shrink Volume, the Unallocated space is behind D rather than C, so extend C drive grayed out, too.

Extend volume greyed out

This is the most common issue feedback by the Windows computer users. In this situation, you need NIUBI Partition Editor to move Unallocated space to behind C drive, and then Extend Volume will be available.

Another reason why Extend Volume grayed out is not supported File System. From Microsoft, only NTFS and RAW partition can be extended with Extend Volume. So Extend Volume is unavailable for FAT32 partition, no matter it is system C drive or any data volume.

FAT32 not supported

C drive does not show Extend Volume

Extend Volume functionality is added from Windows Vista, so in Windows XP and Server 2003, when you right click, C drive does not show Extend Volume.

No Extend Volume

Solution of Extend Volume greyed out for C drive

Actually, it is very easy to solve this problem. If you use Windows 10/8/7/Vista/XP (32 and 64 bit), the free partition manager NIUBI Partition Editor Free can help you. Both NTFS and FAT32 partitions can be extended. To better describe how to fix this issue, I divide the steps into 2 parts.

Part 1 – Unallocated space is behind D

As I said above, this is the most common situation why Extend Volume is grayed out for C drive. To solve this problem, you just need to move the Unallocated space to behind C drive, steps:

Download NIUBI Partition Editor, right click drive D and select Resize/Move Volume.

Resize/Move Volume

In the pop-up window, you’ll see drive D and the adjacent 20GB Unallocated space. On the bottom, you’ll see the disk partition layout.

Before moving

Drag middle position of drive D rightwards:

Move volume D

Unallocate space will be moved to the left side at the same time automatically.

Unallocated moved

Click OK and back to the main window, 20GB Unallocated space is moved to next C drive. Press Apply button on top left to proceed.

Unallocated moved behind C

Now you can extend C drive with Extend Volume in Disk Management or with this free partition manager.

Part 2 – No Unallocated space

If you have not shrank a drive with Shrink Volume to get Unallocated space, run NIUBI Partition Editor directly, which is much easier.

Step 1: Right click drive D and select Resize/Move Volume:

Shrink D

In the pop-up window, drag the left border rightwards to shrink D.

Shrink D

20GB Unallocated space is generated behind C: drive. (if you drag right border of D leftwards, the Unallocated space will be generated behind D)

Unallocated created

Step 2: Right click C drive and select Resize/Move Volume again. In the pop-up window, drag the right border of C: rightwards to combine the 20GB Unallocated space.

Extend C drive

C drive is extended by taking 20GB free space from D. Remember to click Apply on top left.

C drive extended

Tips: The tasks below Pending Operations on bottom left with can be done in Windows without reboot.

If extend C drive grayed out in Windows Server 2016/2012/2008/2003 or Small Business Servers, you need NIUBI Partition Editor Server Edition, Which is the safest and fastest partition software for Windows Server.


Extend c drive greyed out in Disk Management, what to do?
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