How to add more free space to C: drive

By Jordan, Updated on: August 22, 2020

This article introduces how to add space to C drive without losing data. 3 ways to add more 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).

1. Benefit to add more space to system C drive

Most of 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 space to C drive from other partitions. It costs such a long time if you back up everything, delete and recreate partitions, finally restore and verify data.

To add more space to C drive, there are 2 kinds of tools - Windows native Disk Management and third party partitioning software. Disk Management can only help you delete the contiguous partition D and add its space to C drive. If you want to add free space to C drive by shrinking other volume, third party software is needed, learn why.

There are many partitioning software in the market, but you'd better back up in advance and run the safest tool, because there is potential data loss and system damage risk. While re-partitioning disk drive, the parameters of associated disk, partition and files must be modified correctly. Any software error or hardware issue could cause part of the parameters failed 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 with large amount of files.

2. How to add free space to C drive from D or other partition

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 either 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 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 space to C drive from adjacent partition:

Video guide

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

3. How to add space to C drive from E (nonadjacent partition)

In some computers, there is not enough free space in the contiguous volume D, in that 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 E: drive 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, then Unallocated space will be moved to the left side of D.
  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

4. How to add space to C drive partition with another 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 free space to C drive from another disk. No matter you use physical disk or VMware/Hyper-V virtual disk, no software can add space to C drive from a separate disk.

In this case, you have 3 options according to the configuration of your own disk:

  1. If you use physical disk, there's other data volume but it's full, you may move this data partition to another disk, delete this partition and add its space to C drive.
  2. Clone whole disk to a larger one and extend C drive with additional disk space.
  3. 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 at the end of original disk, then follow the steps above to combine into C drive.

Besides adding space to C drive without losing data, NIUBI Partition Editor helps you do many other operations such as merge, convert, defrag, wipe partition, scan bad sectors. To Windows 10/8/7/Vista/XP home computer users, there's free edition, it is the same with professional edition except lacking of 1-Second Rollback technology and bootable USB/CD builder.

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