How to Extend Partition/Volume in Windows Server 2016

by Andy, Updated on: July 19, 2022

Low disk space is common issue in Windows Server 2016 and other versions, especially to system partition C. To solve this problem, you have 2 choices. Back up everything, recreate partitions and restore. It wastes such a long time if you do like that. The better choice is extending partition with free space in other volume. To extend partition in Windows Server 2016, there are 2 choices. Run "Disk Management" or third party disk partition software. Because of many restrictions, Disk Management is not the best choice. In this article, I'll introduce how to extend volume in Windows Server 2016 with both kinds of tools. Select the one that fits for your needs.

About Windows Server 2016 "Extend Volume" function

Disk partitions are allocated when installing Operating System or by server OEM manufacturer. After running the server for a period of time, system C drive is getting full. Originally, you have to back up, recreate partitions and restore everything. It may cost a whole day to accomplish this task.

From Windows Server 2008, Microsoft added new "Extend Volume" function in native Disk Management tool, with which you can increase disk space of the allocated partitions without losing data.

However, only few partitions can be extended because of some limitations of Disk Management. Windows Server 2016 "Extend Volume" function is inherited from old version without any improvement, so many server administrators feedback that they cannot extend partition with this tool. You still need third party software to extend Server 2016 partition in most cases.

Cannot extend volume

How to run Extend Volume in Windows Server 2016 without software

  1. Press Windows + X together on the keyboard and then click Disk Management in the list.
  2. Right click the adjacent partition on the right (such as D:) and select "Delete Volume".
  3. Right click the adjacent partition on the left  (such as C:) and select Extend Volume.
    Extend Volume
  4. Extend Volume Wizard will be launched, simply click Next to continue.
  5. Available disk and space is selected by default, click Next to continue.
  6. Click Finish to confirm and start extending.

In most cases, the left partition can be extended in a short time.

Drive extended

It is easy to extend partition in Server 2016 via Disk Management when there's contiguous Unallocated space, but you cannot get such required space by shrinking any other partition. The only option is deleting the contiguous partition on the right.

Shortages to extend Server 2016 partition via Disk Management

GPT and MBR are common types of hard disk in Windows computer, if your disk is GPT, there are 2 common limitations while extending partition with Server 2016 Disk Management. If your disk is MBR, there are 2 additional limitations.

Cannot extend a partition by shrinking another one

There's another "Shrink Volume" function in Disk Management, many people tried to shrink D drive and got some Unallocated space, but they found that it's impossible to add Unallocated space into C drive. This is the most common issue while extending volume in Windows Server 2016 Disk Management.

Cannot extend volume

As you see in the screenshot, Extend Volume greyed out for both C: and E: drive after shrinking D.

This is because: "Extend Volume" only works when there's adjacent Unallocated space on the right, but "Shrink Volume" cannot make such required space while shrinking partition.

In my computer, the 20GB Unallocated space that shrunk from D drive is non-adjacent to C drive and is on the left of E, so Extend Volume is disabled.

The only way to enable Extend Volume in Windows Server 2016 Disk Management is by deleting the right contiguous partition. Caution: if you installed programs or any Windows services in drive D, do not delete it.

Only NTFS partition can be extended

Extend Volume disabled

NTFS and FAT32 are most common partition type in Windows computers, but both Shrink and Extend Volume functions only support NTFS partition.

That means, if the partition that you want to expand is formatted with FAT32 or other file system, you cannot extend this partition even if there's contiguous Unallocated space on the right.

The partitions that you want to delete and extend must be the same type

This limitation only exists in MBR style disk. The partitions that you want to delete and extend must be the same Primary or Logical partition, otherwise, you still cannot extend partition after deleting the right contiguous volume.

Cannot extend

Extend Volume greyed out

Cannot extend Server 2016 partition past 2 TB

On MBR disk, there's another major shortage. You can only use 2TB disk space even if this disk or RAID array is 4TB or larger. The remaining space is shown as Unallocated in Disk Management. When you right click it, there's no available options. If you want to extend a partition larger than 2TB, follow the method to convert MBR disk to GPT.

Better way to extend partition in Windows 2016 server

With NIUBI Partition Editor Server, there are no such limitations, comparing with Windows Disk Management, it has many advantages such as:

  1. It can shrink and extend both NTFS and FAT32 partitions.
  2. It can make Unallocated space on either left or right side while shrinking partitions.
  3. It can combine Unallocated space to either contiguous partition by 1 step, no matter this partition is NTFS or FAT32, Primary or Logical.
  4. It can move and merge Unallocated space to any non-adjacent partition on the same disk.
  5. Much easier, you just need to click, drag and drop on the disk map.
  6. Merge, copy, convert, defrag, wipe, hide partition, scan bad sectors and much more functions.

There are many software to help extend partition in Windows Server 2016, but few are safe enough including Windows Disk Management. Better than other tools, NIUBI Partition Editor has innovative technologies to protect your system and data such as:

  • Virtual Mode - all operations will be listed as pending for preview, real disk partitions won't be changed until click "Apply" to confirm.
  • Cancel-at-well - if you applied incorrect operations, it doesn't matter, you can cancel the ongoing operations without causing damage.
  • 1-Second Rollback - if any error is detected while resizing partition, it automatically reverts server to original status in a flash. If it happens, your server could back online rapidly without modification.

How to extend partition in Windows Server 2016 without losing data:

  1. Download NIUBI Partition Editor, right click D: drive and select "Resize/Move Volume", drag the left border towards right in the pop-up window.
  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. (All operations before this step only works in virtual mode.)

If want to extend RAID partition in Windows Server 2012 or extend virtual partition in VMware/Hyper-V, follow the same steps, there's no difference.

Watch the full steps to extend Server 2016 partition:

Video guide

If there's no available free space on the same disk, no software can extend volume by adding free space from another separate disk. In that case, follow the steps to extend partition by copying to a larger disk.

In Summary

Windows Server 2016 Extend Volume function can only extend NTFS partition by deleting the right adjacent volume. Because of the inherited limitations, Disk Management cannot extend partition in most cases. To extend volume in Windows 2016 server, NIUBI Partition Editor is the best choice, it helps accomplish this task easily, fast and safely. It also helps merge, move, copy, convert, defrag, hide, wipe partition and much more.