Windows Server 2016 Merge Unallocated Space to C Drive

Published on: November 16, 2019

This article introduces how to merge Unallocated space to C drive in Windows Server 2016, move and add Unallocated space to system partition without losing data.

Windows Server 2016 has built-in Shrink and Extend Volume functions in Disk Management console, but many administrators encountered the problem while resizing partitions with this native tool. The typical example is that they cannot merge Unallocated space to C drive after shrinking D or other partitions. This article introduces why unable to add Unallocated space to C drive in Server 2016 Disk Management and how to solve this problem.

Merge Unallocated space with Server 2016 Disk Management

Comparing with server partition manager software, Disk Management seems to be a semi-finished product, because it has many limitations. First of all, the Extend Volume function can only merge Unallocated space to the left contiguous partition. Secondly, the Shrink Volume function can only make Unallocated space on the right while shrinking partition.

Unallocated space that shrunk from drive D is non-adjacent to C drive and is on the left of drive E, therefore, Server 2016 Disk Management cannot merge Unallocated space to C drive or E.

Both Shrink and Extend Volume functions only support NTFS partition. So, Disk Management can only helps you shrink a NTFS partition to create volume, or extend a NTFS partition by deleting the right contiguous volume.

In addition, if the disk is MBR and drive D is Logical, you still cannot extend C drive after deleting D. (Note: do NOT delete D if you installed programs in it.)

Cannot extend volume

3rd-party software can move partition D towards right, then Unallocated space will be next to C drive, so they can merge non-adjacent Unallocated space to C drive in Windows 2016 server.

Merge Unallocated space to C drive with NIUBI Partition Editor

There are many software that is able to move and add Unallocated space to C drive in Windows Server 2016, however, you'd better back up first and run the safest tool. Otherwise, there's potential data loss risk. Better than other tools, NIUBI Partition Editor has powerful technologies to protect system and data, for example:

While moving Unallocated space behind C drive, all files in drive D will be moved to new locations, too. The more files in it, the longer time to move. Because of the advanced file-moving algorithm, NIUBI is 30% to 300% faster. It is helpful especially when this operation requires server rebooting.

How to move and merge Unallocated space to C drive in Windows Server 2016:

  1. Download NIUBI Partition Editor, right click drive D and select "Resize/Move Volume", drag the middle towards right in the pop-up window. Then Unallocated space will be moved next to C drive.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine Unallocated space.
  3. Click Apply on top left to execute. (Disk partitions won't be modified until click Apply to confirm.)

The pending operations marked as Check can be done in Windows, the ones marked with refresh symbol requires server rebooting.

Watch the video how to operate:

Video guide

The steps are the same no matter you use physical server with SSD, HDD, any types of hardware RAID, or virtual server in VMware/Hyper-V.

Move/Add Unallocated space to C drive from another disk

In few servers, there's no other partitions or not enough free space on the same disk, many people are wondering whether it is possible to move Unallocated space to C drive from another disk. The answer is no.

No software can transfer space between 2 separated disks. When there's no available free space in a disk, there are 2 options:

  1. If you use physical server, follow the steps to copy disk to a larger one and expand partition(s) with additional disk space.
  2. If you run virtual server, follow the steps to increase size of the virtual disk in VMware or Hyper-V. After that, additional space will be shown as Unallocated on the end of disk, then follow the steps in the video above to combine Unallocated space to C drive (and other partitions).

In Summary

To move, add and merge Unallocated space to C drive in Windows 2016 server, the native Disk Management is useless in most cases. To accomplish this task, you'd better back up and run safe software. Besides shrinking, moving and extending partition, NIUBI Partition Editor helps copy, convert, defrag, wipe, hide partition, scan bad sectors and much more.

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