Extend C drive

How to extend C drive with Unallocated space in Windows 10?

The same with previous Windows Operating System, low disk space issue is also very common in Windows 10. After running Windows 10 for a certain time, C drive runs out of space and becomes full. Windows 10 automatically download and install Updates more frequently that previous versions, so you’ll see C drive full in Windows 10 in shorter time. Nobody likes to start over to recreate volumes, instead, you can extend C drive with Unallocated space or free space in other volumes. In this article, I’ll introduce how to extend volume in Windows 10 with builtin Disk Management and 3rd-party free partition manager.

Extend C drive

Cannot extend C drive in Windows 10

From Windows Vista, Microsoft added advanced management functions in Disk Management snap-in. Shrink Volume is used to decrease size of a volume and Extend Volume is used to increase size of a volume. When C drive is running out of space, some Windows 10 users try to shrink D to get Unallocated space and then extend C:

Shrink D

But failed, because when right click C drive, Extend Volume is greyed out.

Extend C grayed

From Microsoft explanation, to extend a drive with Extend Volume, there must be adjacent Unallocated space. After shrinking volume D, the Unallocated space is on the right side of D, of course it cannot be used to expand C drive.

Expand volume by deleting

It doesn’t work by shrinking, some people try to delete volume D to get Unallocated space.

Delete D

It works if volume D is adjacent Primary partition. However, if you do like this, all applications and Windows services point to D stop working after deleting. You’ll lose data if you forget to back up or transfer all files in D to other device.

Cannot extend C drive after deleting

In some situations, you cannot extend C drive even if you delete volume D, for example:

Extend C greyed

The reason when Extend Volume still grayed out is because: volume D is a Logical partition. Besides deleting D, you have to delete all Logical partitions and the entire Extended partition. It is really a bad idea to extend C drive by deleting so many volumes.

Extend C drive in Windows 10 with free partition manager

With free partition manager such as NIUBI Partition Editor Free, you can expand C drive much more easily. If there is Unallocated space in the same disk, you can move it to behind C drive.

DownloadNIUBI Partition Editor Free, right click drive D and select “Resize/Move Volume“. In the pop-up window, drag the middle position rightwards to move it.

Move volume

After that, the Unallocated space will be moved to behind C drive.

You may either expand C drive under Windows 10 Disk Management or continue running this free partition software.

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

Extend C drive

By simply dragging, you can extend C drive with Unallocated space in Windows 10.

Watch the video how to shrink and extend C drive in Windows 10:

NIUBI Partition Editor Free Edition is 100% free for home users, no bundle, no ads, 100% safe and clean. As the most popular free partition software, it helps you resize partition, copy, hide, set active, convert, defrag, check partition and much more.

How to extend C drive with Unallocated space in Windows 10?
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