How to extend C: drive on Windows 10

Updated on: May 17, 2019

This article shows how to extend C drive in Windows 10 (32 & 64 bit) without reinstalling Operating System or losing data. Expand partition C by shrinking D or E drive.

Extend C drive via Windows 10 Disk Management

The same with previous Windows 7, Windows 10 native Disk Management tool has Extend Volume functionality to expand disk partition. However, it is not the best tool because of many limitations, which cause you unable to extend C drive.

The typical example is that Extend Volume is disabled for C drive after shrinking D.

Cannot extend C

  • Extend Volume function can only expand NTFS partition with contiguous Unallocated space on its right side.
  • Shrink Volume can only shrink a partition towards left and produce Unallocated on the right side.

As you see, the 20GB Unallocated is non adjacent to C drive after shrinking D, of course Extend Volume is greyed out.

The only way to enable Extend Volume for C drive is by deleting the contiguous partition (D).

Don't do this if you installed program to this partition. Why not extend C drive without causing damage?

Extend partition C by shrinking D

Better than Windows built-in Disk Management, disk partition software can shrink a partition and produce Unallocated space on either side. Then you can expand C drive with either tool.

Steps to extend C drive on Windows 10 (32/64 bit):

Download and install NIUBI Partition Editor, you'll see the main window with disk partition information and available operations.

Main window

Step 1: Right click drive D and select "Resize/Move Volume", drag left border towards right in the pop-up window.

Shrink D

As you see, Unallocated space is produced on the left side of D.

Shrink D rightwards

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

Extend C drive

As you see, C drive is extended by merging the Unallocated space.

Extend volume C

Step 3: Click Apply on top left to execute, done.

This software is designed to work in its virtual mode, the operations you do will be listed as pending on bottom left, and real disk partitions won't be modified until click Apply to confirm.

Expand C drive by shrinking non adjacent volume

If you can't get enough free space from the contiguous partition D, it doesn't matter. You may shrink any non-adjacent partitions in the same hard disk.

For example, how to shrink E to expand C drive in Windows 10:

  1. Right click partition E: and select "Resize/Move Volume", drag the left border towards right in the pop-up window. Then you'll get Unallocated space on the left side of E. (Similar with Step 1 above)
  2. Right click partition D: and select "Resize/Move Volume", drag the middle position towards right in the pop-up window. Then Unallocated space will be moved next to C drive.

Move drive D

Then follow the Step 2 above to extend C drive.

Extend volume C with other disk

If there is no other partition, or not enough unused space in all other partitions in the same disk, NO partitioning software can extend a partition by taking space from another separated hard disk.

However, there's still a way with NIUBI Partition Editor by cloning this disk to another larger one. You can extend partition C and other data volumes with extra disk space. Watch the video how to expand C drive by cloning:

Video guide

In Summary

To extend C drive in Windows 10 (32 & 64 bit), the native Disk Management tool can only accomplish by deleting the continuous partition. You can't do do this in most cases, so you'd better run NIUBI Partition Editor. Select the right way according to your disk partition structure.