Cannot extend C

Cannot extend volume in Windows 7 – solution

Low disk space is very common in all Windows versions. Better than Windows XP, Windows 7 native Disk Management utility has Shrink and Extend Volume feature to change partition size without reinstalling. However, many people feedback that they cannot extend volume in Windows 7 Disk Management. The typical example is that they cannot extend C drive after shrinking D, because Extend Volume is greyed out.

Can't extend volume

In this article, I’ll explain why you can’t extend volume with Windows 7 Disk Management and how to solve this problem step by step.

Why Extend Volume doesn’t work

Search by Google or in some technical forums, you’ll find that many people encountered the same issue but the disk partition configurations are different, because there are several reasons why cannot extend volume in Windows 7 Disk Management, I’ll explain one by one.

Reason 1 – no adjacent Unallocated space

From Microsoft, Windows 7 built-in Extend Volume functionality only works when there is adjacent Unallocated space on the right side

Before extending a drive, there must be some usable disk space and Unallocated is such kind of space. As the name, this disk space is not allocated to any drive. To get Unallocated space, you may either delete or shrink a drive. The difference is: all disk space of a drive will be converted to Unallocated after deleting, but only part of unused space will be converted to Unallocated.

That means, you won’t lose data by shrinking a volume, this is is the reason why many people want to extend C drive by shrinking D. But, it is impossible by Disk Management. After shrinking D with Shrink Volume, Unallocated space is on the right side of D, so it is not adjacent to drive C, of course you cannot expand C with Extend Volume. This is the most common problem that Windows 7 users encountered.

Cannot extend volume

From the screenshot of my Windows 7 laptop, I cannot extend volume C, because the Unallocated space is nonadjacent. I cannot extend drive E, because the Unallocated space is on the left side.

Reason 2 – FAT32 partition is not supported

In fact, Extend Volume only supports NTFS partition,  FAT32 and any other types of partitions cannot be extended even if there is adjacent Unallocated space on the right side. However, this issue is only common for data drives, because most of system C drive is formatted as NTFS.

FAT32 not support

Reason 3 – restriction between Primary and Logical partition

Windows 7 format hard disk as MBR when installing, but comparing with GPT disk, MBR style disk has a serious restriction. There are only 4 entries in Master Boot Record, from which Operating System can easily locate the position of each drive. It sounds simple but cause you can only create 4 Primary partitions or 3 Primary partitions plus an Extended partition. If you have created 4 Primary partitions already, you cannot create new drives. If you have created 3 Primary partitions, all new drives can only be created as Logical partition. Extended partition works like a container and all Logical partitions should be in it.

To show you this restriction, I deleted drive E. As you see, drive D is Primary and original E is Logical, so I cannot extend volume D. Different with Primary partition that is converted to “Unallocated” after deleting, Logical partition will be converted to “Free space”.

Strictly speaking, a Logical drive is just a block of the Extended partition and simulated as a partition. Only when the entire Extended partition is deleted, the disk space will be converted to Unallocated.

Extend volume inativate

If you want to expand a data drive, you may transfer files and delete the adjacent drive on the right side, so Extend Volume is enabled. It works when you extend a Primary partition by deleting the adjacent Primary partition, or extend a Logical partition by deleting the adjacent Logical partition. But you cannot extend a Primary partition by deleting a Logical partition, or extend a Logical partition by deleting a Primary partition.

What to do when you cannot extend volume

It seems complicated but it is very easy to solve this problem with partition manager software such as NIUBI Partition Editor.

If you have shrank drive D and got Unallocated space, but unable to extend C drive because Unallocated is nonadjacent, follow the steps below:

Extend volume disabled

Step 1: Right click drive D and select Resize/Move Volume, drag the middle position rightwards in the pop-up window.

Move partition D

Unallocated space is moved to the left side of drive D.

Drive D resized

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

C drive is extended by merging the Unallocated space.

C drive resized

What to do if cannot extend volume due to not supported FAT32 partition or the restriction between Primary and Logical partition?

In one word: if the Unallocated or Free space is adjacent on either side, simply right click this drive and select “Resize/Move Volume”, drag either border towards the other side to combine the Unallocated or Free space. If the drive that you want to extend is nonadjacent to these space, simply drag the middle position in the pop-up window to move this drive and then combine these space.

If you still do not understand how it works, watch the video:

In Summary

The semi-finished Extend Volume has many limitations that cause you cannot extend partition in Windows 7 Disk Management. To solve this problem, run NIUBI Partition Editor to move partition and combine Unallocated space. You just need to drag and drop on the disk map.

Download to try