How to merge disk partitions in Windows Server 2016?

The most common issue in Windows Server 2016 is lacking of free space – C drive is filling up after running the server for a period of time. In this situation, some people find that there is plenty of free space in the adjacent volume D. They wondering if it is possible to merge D into C, so there will be more free space in C drive. Yes, it is a good idea and actually it is possible. However, it is not the best idea to merge Server 2016 partitions, instead, you’d better resize volumes to increase C drive free space. In this article, I’ll introduce how to  merge partitions in Windows Server 2016, as well as the shortage of combining volumes, the advantage to resize volumes.

Merge partitions in Server 2016 Disk Management

Windows Server 2016 Disk Management provide Shrink and Extend Volume functions, which can be used to merge partitions indirectly.

Note: this is just an example to combine partitions in Server 2016, it is not recommended to operate in destructive way. Read all paragraphs and then decide if you want to merge volumes like this.

Right click Windows on bottom left and select Disk Management:

Open disk management

  1. Back up or transfer all files in D to other place.
  2. Delete drive D
  3. Right click C drive and click “Extend Volume”.
  4. Finish the Extend Volume Wizard

When it complete, all disk space of D will be merged into C: drive.

Cannot merge Unallocated space in special situation

Even if you decide to merge C and D in the destructive way, in some special situations, you still cannot merge the partitions after deleting D, for example:

Delete drive D

Extend Volume is grayed out even if you delete volume D.

Cannot extend C

Why? Because volume D is Logical and it is in Extended Partition. After deleting D, the disk space shows as Free instead of Unallocated. In this special situation, you have to delete other Logical partition E: as well as the entire Extended Partition. However, with partition software you can merge the free space into C drive without deleting other volumes.

Merge volumes with partition software

  1. Download and install NIUBI Partition Editor.
  2. Right click C drive and select “Resize/Move Volume” function.
  3. In pop-up window, drag right border rightwards to hold the free space, done.

Extend C drive

Resize volume instead of combining partitions

As I said in the beginning, it is not the best idea to merge Server 2016 partitions, instead, you’d better resize volumes to increase C drive free space, reasons:

  1. Drive D will be deleted, all services and applications running from it stop working.
  2. It costs much time to transfer files to and back from other place.
  3. You have to delete several volumes besides of D in some special situations.

I always suggest operate in non-destructive way. With partition software, you can shrink D to get free space without deleting it, so everything keeps intact.

Step 1. Right click volume D and select “Resize/Move Volume“.

Select Resize

Step 2: In the pop-up window, drag left border rightwards to shrink it.

Shrink d drive

Drag to shrink

Click OK, 20GB Unallocated space took out from D.

Unallocated created

Step 3: Right click C and select “Resize/Move Volume” again. In the pop-up window, drag the right border rightwards to hold the Unallocated space.

Extend C drive

Extend C

Step 4: Click OK, free space from D added into C drive. Click Apply on top left to execute, done.

C drive extended

In Summary

You can merge partitions in Windows Server 2016 Disk Management, but it is not the best way. To increase C drive free space, the best idea is resizing instead of merging partitions. So everything keeps intact.

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