Windows Server 2016 Extend Volume Greyed Out (Reason & Solution)

by Lance, Updated on: October 1, 2021

Windows native Disk Management has Shrink Volume and Extend Volume functions to help change partition size without losing data (in most cases). However, many people feedback that Extend Volume greyed out in Windows Server 2016 Disk Management. The typical example is that Extend Volume is disabled for C drive after shrinking partition D or E. This article explains all probable reasons why Extend Volume is disabled in Windows Server 2016 Disk Management and how to fix this issue easily.

1. Why Extend Volume greyed out in Windows Server 2016

No adjacent Unallocated space (both on MBR & GPT disk)

A 256GB physical hard disk cannot be increased to 512GB, so before extending a partition, you must shrink or delete another one to get Unallocated space. By deleting a partition, all its disk space will be converted to Unallocated, meanwhile all files in it will be lost. By shrinking a drive, only part of the free space will be converted to Unallocated and you won't lose files.

If you did not shrink or delete other volume to get Unallocated space, of course Extend Volume is grayed out in Windows Server 2016.

Extend Volume disabled

Many server administrators did shrink drive D/E before extending C: drive, but Extend Volume is still disabled in Windows Server 2016.

Extend Volume greyed out

Shrink Volume function can only make Unallocated space on the right while shrinking partition. Extend Volume function can only combine Unallocated space to the contiguous partition on the left. Therefore, Extend Volume is disabled for C: and E: drive after shrinking D.

Only NTFS is supported (both on MBR & GPT disk)

Extend Volume function only supports extending NTFS and RAW (no file system) partitions, so another common FAT32 partition and any other types of partitions can't be extended even if there is adjacent Unallocated space on the right.

Extend Volume disabled

To show you this shortage, I formatted D: drive from NTFS to FAT32. As you see in the screenshot, there's 20GB Unallocated space behind D drive, but Extend Volume greyed out in Server 2016 Disk Management, too

In most of Windows servers, system C drive is formatted with NTFS, so this issue is just common to data drives.

Restriction between Primary and Logical partition (on MBR disk)

Because it doesn't work by shrinking a volume, some people are wondering whether it works by deleting partition instead. If on GPT disk, yes, but if you use MBR disk, it depends.

In GPT disk, all partitions are Primary, but in MBR disk, there may be Primary and Logical partition. If the type of partition that you want to delete and extend are different, you cannot extend partition after deleting another one.

Extend Volume greyed out

As you see in the screenshot, Extend Volume is disabled for D: drive after deleting the right contiguous partition E.

This is because:

On MBR disk, Free space that deleted from a Logical drive can't be extended to any Primary partition. Unallocated space that deleted from Primary partition can't be extended to any Logical drive.

2TB limitation on MBR disk

Nowadays, hard disks are much cheaper and larger, so it is very common to use 4TB single disk or over 10TB RAID array. If you initialized a disk as MBR, you can only use 2TB disk space in Disk Management.

Extend Volume grayed

As the screen shot shows, drive H is formatted with NTFS and there is adjacent contiguous Unallocated space on the right, but Extend Volume is grayed out.

To use full 2TB+ disk space or extend a partition larger than 2TB, you need to convert disk from MBR to GPT in advance.

2. What to do when Extend Volume is disabled in Server 2016

Open Disk Management and find out your server disk partition configuration. Follow the corresponding solution below according to your own disk partition structure. Each solution has a video guide.

Solution 1: Move Unallocated space

How to fix Extend Volume greyed out in Windows Server 2016 after shrinking D drive:

  1. Download NIUBI Partition Editor, right click D: drive and select "Resize/Move Volume", drag the middle towards right in the pop-up window. Then Unallocated space will be moved to behind C drive.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine this Unallocated space.
  3. Click Apply on top left to execute. (All operations before this step only work in virtual mode.)

Video guide

Solution 2: Resize partition with NIUBI

How to fix Extend Volume greyed out in Windows Server 2016 because of non-supported FAT32 partition or the restriction between Primary and Logical partition:

  1. Run NIUBI Partition Editor, right click the adjacent partition and select "Resize/Move Volume".
  2. Drag the border towards other side to combine the adjacent Unallocated space.
  3. Click Apply on top left to execute.

Video guide

Solution 3: Convert MBR disk to GPT

When you cannot extend a partition past 2TB in Windows Server 2016, follow the steps below:

  1. Run NIUBI Partition Editor, right click front of this disk and select "Convert to GPT Disk".
  2. Run "Resize/Move Volume" function and combine Unallocated space to the partition(s) that you want to expand.

Video guide

3. Take care of data while extending partitions in a server

Unlike read-only program, partitioning software will modify the parameters of associated disk, partition and files. Therefore, there's potential system damage and data loss risk especially when you shrinking and moving partitions. Remember to back up in advance and run safe partition software.

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

It is 30% to 300% faster because of the advanced file-moving algorithm, it's very useful when you move partition with large amount of files. Besides help fix Extend Volume greyed out issue in Windows Server 2016/2019/2012/2008, it helps you merge, copy, convert, hide, wipe partition, scan bad sectors and much more.