Increase C drive free space in Windows 10

Updated on: May 17, 2019

This page shows how to increase C drive space in Windows 10 (32 & 64 bit) without losing data. Increase C drive by transfer unused space from D, E or other partition volume.

No matter you use OEM laptop/desktop or build the computer DIY, disk space of system C: drive and other data volumes are allocated. However many types of files write in to system C drive, so it'll become full some day. In this case, you can increase C drive space in Windows 10 without reinstalling Operating System and programs.

To increase partition size in Windows 10, there are two choices: Windows 10 native Disk Management and third party partition software such as NIUBI Partition Editor. In this article, I'll introduce several ways to increase C drive disk space in Windows 10 (32 bit and 64 bit) with both tools.

Increase disk space with Disk Management

Windows 10 Disk Management has build-in Extend Volume functionality which can be used to increase partition size without losing data, but not every drive can be extended. In fact, Extend Volume only works when disk partition configuration meets the requirements below:

Because of the restrictions of Extend Volume, another function Shrink Volume can only make Unallocated space on the right side when shrinking a partition. So you can't extend C drive by shrinking D in Disk Management. The only option is by deleting partition D to get adjacent Unallocated space.

2 points you should know before doing this:

  • Back up or transfer all files in the adjacent partition (D:) before deleting.
  • Do NOT delete D if you installed programs to it.

If you can enlarge C drive by deleting D, follow the steps below:

  1. Press Windows and X on your keyboard, then select Disk Management from the list.
  2. Right click partition D: and select "Delete Volume". (Disk space will be converted to Unallocated if D is Primary partition)
  3. Right click partition C: and select "Extend Volume". (Extend Volume Wizard will be opened)
  4. Simply click Next till Finish to execute.

Extend volume wizard

With 3rd party software you can shrink D to expand C drive without deleting.

There is potential system and data damage risk while resizing disk partitions, so remember to make back up. Better than other software, NIUBI Partition Editor provides unique 1 Second RollbackVirtual Mode and Cancel-at-well technologies to protect system and data.

Increase C drive space from D or E

In most of the computers, there are other partitions in the same disk, then you can increase C drive by transferring unused space from D, E or any other one. Operating System, programs and associated setting, as well as everything else keep the same. No other operations are needed even if you use any types of hardware RAID arrays.

Download NIUBI Partition Editor and you'll see the disk partition with structure and other information. There are 3 partitions C, D and E in Disk 0.

Main window

Option 1: increase partition C from D

D is the adjacent partition behind C drive. Original drive C is 30GB and D is 50GB.

Steps to increase C drive space from D in Windows 10:

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

Shrink D

20GB unused space is converted to Unallocated 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

Then C drive is increased to 50GB by merging the Unallocated space.

Extend volume C

This software is designed to work in its virtual mode and the operations are listed as pending on bottom left. To modify real disk partition, you need to click Apply to confirm.

Option 2: increase partition C from E

If there is not enough unused space in the adjacent partition D, you can get from other nonadjacent volume. Right click drive E and follow STEP 1 to make Unallocated space on the left side. Then you need an additional step to move Unallocated space to the left side of D.

To do this, right click drive D and select "Resize/Move Volume", drag middle position rightwards in the pop-up window.

Move drive D

Unallocated space will be moved next to C drive, then follow STEP 2 above to expand C drive.

Increase C drive size by cloning

If there is no other partition, or not enough unused space in all other partitions in the same disk, you can clone to another larger disk with NIUBI, and then increase C drive with extra disk space.

In Summary

To increase C drive disk space in Windows 10, the native Disk Management only works in special condition, so you need third party professional partition software in most cases. As the safest partition tool, NIUBI Partition Editor provides powerful data protection technologies and several ways to resize/extend partition.