Increase C drive space

How to move free space from D to C?

Recently, some people ask me whether it is possible to transfer or move free space from a drive to another one without reinstalling or losing any data. Yes, it is a good idea and nobody likes to start from scratch. The answer is definitely yes. However, the first thing you should concern is not how but the data. To extend a drive, there must be Unallocated or free space in the same hard disk. In most of the computers, there is a drive (D: or other) behind C drive, so in this article, I’ll show you how to move free space from drive D to C easily and safely. This method is valid for Windows 10/8/7/Vista/XP and Server 2016/2012/2008/2003.

Move space D to C

Take care of your data

It doesn’t matter if you use a new computer or resize volume for new disk drives, but you should pay attention to data safety if you want to move free space from D to C. Obviously, you have run the computer for a long time, so there must be many important files such as family photos and videos, work documents. If it is a server, there are large amount of files that you cannot lose.

There is risk of system damage and/or data loss if you use partition software without data protection ability. If any software error or hardware issue happen while resizing and moving partition, it causes part of the parameters of this disk, volume or files failed to be modified, in this case, you cannot boot Windows or open this volume, files in this volume will be lost.

To complete this task, NIUBI Partition Editor is the best choice. The built-in 1 Second Rollback technology can automatically roll back the computer to original status immediately, if any software or hardware issue happen. That means, the computer can recover without damage rapidly. This ability is especially important to a server for data protecting and fast recovering.

How to move free space from D drive?

Download NIUBI Partition Editor and you’ll see all local and removable storage device that are connected to this computer.

In this computer, there are several volumes in Disk 0, original C: drive is 39.4GB and D is 50GB.

Right click drive D and select Resize/Move Volume:

Shrink D

You’ll see disk partition layout on the bottom in the pop-up window.

Original drive D

Drag the left border rightwards on the partition bar below Size and Location on the top.

Shrink D

20GB free space is moved out from D and converted to Unallocated.

Volume D shrank

Click OK and back to the main window, as you see, 20GB Unallocated space is created on the right side of volume C:

Unallocated created

How to move free space to C drive?

Right click C drive and select Resize/Move Volume again. In the pop-up window, you’ll see C drive and the adjacent 20GB Unallocated space:

C drive and Unallocated

Drag the right border of C: rightwards

Extend C drive

20GB Unallocated space is combined into C drive.

Merge Unallocated

Click OK and back to the main window, press Apply on top left to proceed, done.

20GB free space is moved from D and added into C drive.

C drive extended


  1. To avoid mistake, the operations won’t be done immediately, you need to click Apply to confirm.
  2. You can undo, redo or cancel the operations listed below Pending Operations before clicking Apply.
  3. The operations with can be done in Windows without reboot.

By several clicks and drags, you can move free space from D to C without losing data. Operating System, programs, settings and anything else keep the same.

If you use any hardware RAID such as RAID 0, 1, 5, 10, do not break the raid array, just follow the steps above.