C drive full

Can’t/unable to extend volume in Windows 10

Nowadays, many people insert SSD for Windows 10, or get from computer manufacturer. It is a helpful to improve computer performance. However, comparing with traditional mechanical disk, SSD is much smaller because it is still expensive. So the disk drives are more likely running out of space, especially for the system C drive.

To help solve this problem, Microsoft adds Shrink and Extend Volume features in Disk Management snap-in. However, many people said that they cannot extend volume with this utility. The typical example is that they can’t extend volume C after shrinking D.

In this article, I’ll show you why you unable to extend volume in Windows 10 Disk Management, and how to solve this problem fast and easily.

Can't extend volume

Why cannot extend volume C

To most of the Windows 10 laptop and desktop, the reason why you unable to extend C drive with Extend Volume functionality is because no adjacent Unallocated space. Before extending a drive, there must be Unallocated space. If you try to expand C drive without deleting or shrinking other drive to get Unallocated space, of course it is possible.

Programs or some Windows services are running from D, so you cannot get Unallocated space by deleting. Instead, you have to shrink D, then part of the unused space of D will be converted to Unallocated. However, many people have shrank D and got such space, but Extend Volume is still disabled for C drive. Remember the rule: Extend Volume ONLY works when there is adjacent Unallocated space on the right side.

To show you the truth, I shrank D in my Windows 10 laptop.

Extend Volume greyed out

As you see in the Disk Management:

  • I cannot extend volume C, because the Unallocated space is nonadjacent.
  • I can’t extend volume E, because Unallocated space is on the left side.

Tips To enable Extend Volume for C drive, you just need to move Unallocated space to the left side of D.

Why can’t extend volume D

Actually, there is no difference extending system C drive or any data drives with Extend Volume. The same limitation: you cannot extend a drive by shrinking another one, but, you can achieve by deleting.

If you want to extend D or other data drive, you can transfer files in the adjacent partition and delete it, then Extend Volume becomes valid. However, if drive D is FAT32, you cannot extend it.

Extend Volume disabled

The truth Extend Volume only supports NTFS partition, FAT32 and other types of partitions cannot be extended. If your hard disk is MBR, you cannot extend Primary partition D by deleting the adjacent Logical drive (learn why).

What to do when unable to extend volume

In fact, it is very easy to solve this problem with professional disk partition software such as NIUBI Partition Editor. You just need 1 or 2 steps to drag and drop on the disk map.

Solution 1 – move Unallocated space

When you shrinking D with Shrink Volume in Windows 10 Disk Management, Unallocated space can only be produced on the right side of D. But to expand C drive with Extend Volume, Unallocated space must be on the left side of D. With NIUBI Partition Editor you can move the Unallocated space from right to left side, here we go.

Step 1: Download NIUBI Partition Editor, as you see, there is 20GB Unallocated space behind drive D. Right click D and select “Resize/Move Volume“.

Resize/Move Volume

In the pop-up window, drag the middle position towards the right side.

Move drive 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 drive

Click OK, the 20GB Unallocated space is combined into C drive.

C drive extended

Solution 2 – combine Unallocated space

Better than Disk Management, NIUBI Partition Editor supports both NTFS and FAT32 partitions. So if you can’t extend volume in Disk Management because this volume is FAT32, run “Resize/Move Volume” feature of NIUBI to combine the Unallocated space directly (similar with Step 2).

If you cannot extend drive E because Unallocated space is on left side, drag the left border leftwards, then Unallocated space will be combined to E.

Increase drive E

In Summary

Comparing with professional partitioning software, the native Disk Management is like a semi-finished utility. Because of the limitations of Shrink and Extend Volume, you cannot extend volume in most conditions. With NIUBI Partition Editor, you just need 1 step to combine the adjacent Unallocated space. If you cannot extend partition C after shrinking D, move the Unallocated space to the other side and then combine it to C drive.

Download to try

What to do when you cannot extend volume in Windows 10?
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