Shrink D to extend partition C in Windows Server 2012

Updated on: November 16, 2019

This article introduces how to shrink volume D: to extend C: drive in Windows Server 2012 without losing data. Move and transfer disk space from D to C.

Can't shrink D to expand C in Server 2012 DM

When system partition C is getting full, you may extend it with free unused space in other volumes. So, you can solve this problem without wasting a long time to recreate partitions and restore from backup.

There are Shrink Volume and Extend Volume functions in Server 2012 native Disk Management to resize partitions. However, if you want to extend C: drive by shrinking D with this tool, it is impossible.

While shrinking a partition with Shrink Volume in Disk Management, Unallocated space can only be made on the right side. Extend Volume can only combine Unallocated space to the left contiguous partition.

As you see, Extend Volume is disabled for both C: and E: drive after shrinking D, because C is nonadjacent and E is on the right side of this Unallocated space.


  • Both Shrink and Extend Volume support NTFS partition only.
  • If partition D is Logical, Disk Management still cannot extend C drive even by deleting it.

Extend volume disabled

Shrink D to extend C drive with NIUBI

Comparing with Server 2012 Disk Management, NIUBI Partition Editor is much more powerful:

Download it and you'll see all disk partitions with structure and other information in the main window. Original C: drive is 40GB and D is 70GB.

NPE Server

Available operations to selected disk or partition are listed on left side or by right click. To shrink and extend partitions, you just need to drag and drop on the disk map.

Steps to shrink partition D and expand C in Windows Server 2012:

Step 1: Right click drive D: and select "Resize/Move Volume", drag left border towards right in the pop-up window. (or enter an amount manually)

Shrink D

Then partition D is shrank to 50GB and 20GB Unallocated space is make on its left side.

Drive D shrank

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 extended to 60GB by merging Unallocated space.

C drive extended

Click Apply on top left to execute, done.

If the adjacent partition is E: in your server, the steps are exact the same with above, just replace D with E.

Better than other tools, NIUBI Partition Editor has unique technologies to protect system and data:

While shrinking partition D, all files in it should be moved to new locations. It may costs long time if there are large amount of files in it. NIUBI is much faster because of its special file-moving algorithm.

Method when C and D are in different disk

If drive C is in Disk 0, but partition D is in Disk 1, or in other word there is no other partition in the same disk of C drive. No partitioning software can extend C drive with D or other partition from another separated disk. The separated disk here means Disk 0, 1, 2, etc. that shown by NIUBI, no matter they are physical disk or RAID array virtual disk.

In this case, you can clone disk to a larger one with NIUBI Partition Editor and then extend C drive with extra disk space.