Add space to system C: drive

By Jordan, Updated on: January 21, 2020

This article introduces how to add space to C drive without losing data. 3 ways to add free space to system partition C from D, E or from other disk.

Applies to: Windows 10, Windows 8, Windows 7, Windows Vista, Windows XP, Windows Server 2019, Windows Server 2016, Windows Server 2012 (R2), Small Business Server 2011, Windows Server 2008 (R2) and Windows Server 2003 (R2).

Benefit to add disk space to system C drive

Most of the Windows computer users encountered the problem that system C: drive is running out of space and the annoying Low Disk Space alert pops up frequently. When it happens, the fastest way to solve this problem is by extending C drive. That means add more free space to C drive from other partitions. It costs such as long time if you back up everything, delete and recreate partition, finally restore and verify data.

However, not every software can complete this task well. There is data loss and system damage risk while re-partitioning disk drives with 3rd-party program. To resize partitioned drives, the parameters in MBR, DBR and other place of associated disk, partition and files should be modified correctly. Any software error or hardware issue causes part of the parameters unable to be modified. If it happens, system, partition and/or data will be damaged.

Thanks to the unique 1 Second Rollback, Cancel-at-well and Virtual Mode technologies, NIUBI Partition Editor keeps everything intact after resizing partitions, furthermore, it is much faster because of the advanced file-moving algorithm. It is helpful especially to a Windows server.

How to add free space to C drive from D drive

In most of PCs and servers, there's another partition such as D or E on the same disk. And in most cases, there's plenty of free space in this partition. You can shrink this partition, then part of free unused space will be converted to Unallocated, and then you can add this Unallocated space to C drive. During this process, Operating System, programs and anything else keep the same with before.

Steps to add space to system C drive from D (the contiguous partition):

  1. Download NIUBI Partition Editor, right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window. (Or enter an amount in the box of Unallocated space before). Then Unallocated space will be made on the left side of D.
  2. Right click C: drive and select Resize/Move Volume again, drag the right border towards the right side in the pop-up window, then Unallocated space will be added into C drive.
  3. Click Apply on top left to execute. (Any operations before this step only work in virtual mode.)

Video guide to add disk space to system C drive:

Video guide

If the contiguous partition is E in your computer, simply replace D with E in the steps above.

Add space to C drive from nonadjacent partition

In some computers, there is not enough free space in the contiguous volume D, in the case, you can shrink any nonadjacent partition on the same disk. Before adding Unallocated space to C drive, there's an additional step to move partition D.

Steps to add space to C drive from E (the non-adjacent partition):

  1. Shrink drive E and make Unallocated space on the left with "Resize/Move Volume" feature.
  2. Right click D: drive and select "Resize/Move Volume", drag the middle towards right in the pop-up window.
  3. Right click C: drive and add Unallocated space into it with "Resize/Move Volume".
  4. Click Apply to take effect.

Video guide to add free space to C drive from nonadjacent volume:

Video guide

Add space to system C drive from other disk

In few computers, there's no data volume on the same disk, or the data volume(s) are full. Some people are wondering if it is possible to add space to C drive from another hard disk drive. No matter you use physical disk or VMware/Hyper-V virtual disk, no software can add space to C drive from another separated disk.

In this case, you have 2 options according to the type of your disk:

  1. If you use physical disk, follow the steps to clone disk to a larger one, while cloning you can add extra disk space to C drive.
  2. If you use virtual disk, follow the steps to increase disk size for VMware or Hyper-V. After that, additional disk space is shown as Unallocated on the end of original disk, then follow the steps above to combine into C drive.

As a disk partition management toolkit, NIUBI Partition Editor helps you do many other operations. To Windows 10/8/7/Vista/XP home computer users, there's free edition (100% clean without any bundles).