Shrink D extend C

How to shrink volume D to extend C without losing data?

In most of Windows computers, if you did not create a large C: drive and optimize it regularly, you’ll encounter the problem that system C: drive is running out of space sooner or later. What to do when it happens? Nobody likes to start from scratch. Some skilled computer users have heard of partition software that is able to resize the partitioned drive without reinstalling Windows. However, few people know which tool is the right choice and how to do this, so in this article, I’ll show you how to shrink D: to extend C drive without losing data. This easy method is valid for Windows 10/8/7/Vista/XP and Server 2016/2012/2008/2003 (32 & 64 bit).

Shrink D extend C

Cannot shrink D and extend C in Disk Management

In Windows XP and Server 2003 Disk Management console, you can only do basic operations such as create, delete and format partition, so you cannot shrink volume D and extend C with it. Many skilled users found that there are new functionalities in Windows 10/8/7/Vista and Server 2016/2012/2008 Disk Management. Yes the new Shrink Volume and Extend Volume can be used to resize the existing volume without losing data, however, you still cannot shrink drive D to expand C. When you right click C drive after shrinking D, Extend Volume is grayed out:

Extend Volume grayed out

As you see, Extend Volume is disabled for C drive, why? From Microsoft explanation, to enlarge a drive with Extend Volume, there should be adjacent Unallocated space on the right side. Unallocated space can only be generated on the right side of D after shrinking, of course you cannot extend C: drive until moving the Unallocated space to the left side of D.

So you need 3rd-party program to complete this task. For Windows 10/8/7/Vista/XP users, there is free partition software such as NIUBI Partition Editor Free.

How to shrink volume D:

Download NIUBI Partition Editor and you’ll see all local and removable storage device that are connected to this computer. In my Windows 10 laptop, original C: drive is 39.4GB and D is 50GB.

Right click drive D and select Resize/Move Volume:

Shrink D

In the pop-up window, you’ll see disk partition layout on the bottom.

Original drive D

Drag the left side of D rightwards on the partition bar below Size and Location on the top.

Shrink D

Volume D is shrank, 20GB free space is released 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

Better that Windows Disk Management, you can create Unallocated space on either right or left side with NIUBI Partition Editor.

How to extend 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 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. As you see, drive D is reduced to 30GB and drive C is increased to 59.4GB.

C drive extended


  1. The operations work in virtual mode, only after clicking Apply, the disk partition will be modified.
  2. Have you seen the operations listed below Pending Operations on bottom left? You can undo, redo or cancel them.
  3. The operations with tick can be done in Windows without reboot.

What about shrink E: to extend C?

In most conditions, there is plenty of free space in the adjacent volume D, but if there is not enough there, can you shrink drive E to expand C? Yes, of course, watch the video:


It is very easy to shrink either E or D drive to extend C, but you should pay attention to data safety. There is risk of system damage and data loss while re-partitioning disk drive. Either software related error or hardware issue such as power failure will cause disaster, but backup software is not enough especially for Windows Server. It causes such a long time to restore and verify data if damage happens. Thanks to the unique 1 Second Rollback protection technology, NIUBI Partition Editor can automatically roll back the computer to the status before repartitioning in one second. Nothing will be changed or lost if any software or hardware issue occur, so it is the unique program that can ensure 100% system and data intact, this is the reason why it is recommended as the safest and best Windows partition software.