How to Fix "Extend Volume Greyed out" on Windows Server 2016

Try to extend volume in Windows Server 2016, but find the "Extend Volume" option grayed out in Disk Management. Don't worry, we will tell you why the option is unavailable and how to fix the "Extend Volume" greyed out issue in Server 2016 and other Windows Server systems.


By Dervish / Updated on March 7, 2024

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[Error] Extend volume greyed out on Windows Server 2016

When there is not enough space on the disk partition on Windows Server 2016, especially the system (C) partition, you may want to extend the partition with the built-in tool Disk Management that is equipped with the “Extend Volume” feature. Unfortunately, when you attempt to extend the C drive, you are most likely to find out that the "Extend Volume" option greyed out on Windows Server 2016. What caused this problem and how to fix it effectively? The following content will explain both of them clearly.

Why Disk Management Extend Volume greyed out on Server 2016?

Although Disk Management offers “Extend Volume” function, it can only work under some specific conditions. Namely, when your disk partition structure meets the conditions, then you can successfully extend the selected partition via this feature. Otherwise, the “Extend Volume” option will be grayed out. 

▶ Condition 1: The extend volume or shrink volume feature only works with NTFS file system. If the partition you want to extend is not formatted with NTFS, the Extend Volume option will be grayed out.

Extend Partition 1

▶ Condition 2: It is unable to extend volume in Windows Server 2016 when there is no contiguous unallocated space or free space on the hard drive.

Extend Partition 2

▶ Condition 3: The unallocated space should be on the right adjacent side of the target partition to be extended. If the contiguous unallocated space is on the left side, the "Extend Volume" option will be grayed out.

Extend Partition 3

▶ Condition 4: If you want to extend a primary partition, the Extend Volume will not be available when there is a free space (in the extended partition) instead of unallocated space after the partition needs extending. Similarly, it will not work when you try to extend a logical partition, but unallocated space is in the way.

Extend Primary Partition

How to fix “Extend Volume greyed out” in Server 2016

Based on the possible reasons for which that you are unable to extend volume on Server 2016, generally, the following two methods can help solve this problem.

① Convert FAT32 volume to NTFS before extending

To change the file system of the target volume from FAT32 to NTFS, you can use Command Prompt.

Step 1. Find the letter of partition you want to convert in Windows File Explorer or Disk Management.

Step 2. Press the Windows logo key + R to open the Run dialog box.

Step 3. Input “cmd” and press Enter to open the command prompt window.

Step 4. At the command line prompt, type convert [drive letter]: /fs:ntfs. For example, if the letter of the drive you want to convert is D, you would type "convert D: /fs:ntfs".

Cmd Convert Fat32 To Ntfs

Note: there are no corresponding commands to convert NTFS back to FAT32. To do so, you have to back up required files and reformat this drive again, or turn to an “NTFS to FAT32 Converter”.

② Delete the partition behind the target volume

When there is no unallocated space on the right adjacent side of the aim partition, the "Extend Volume" option will be unavailable. Since Disk Management does not allow you to move partition, you need to delete the partition that locates right behind the partition you wish to extend. Then the “Extend Volume” will be available in Disk Management. But before that, you should make sure you backup the partition you will delete.

Delete Volume Server

A better way to avoid "Extend Volume Greyed Out" on Windows Server 

Although CMD and Disk Management can solve the "Extend Volume" greyed out issue on Server 2016, it can cause data loss by accident. So here is a better solution - AOMEI Partition Assistant Server. This powerful Server partition manager is compatible with Windows Server 2022/2019/2016/2012/2008/2003.

Much more advanced than Windows Server Disk Management, it can extend partitions formatted with either FAT32 or NTFS. Besides, it comes with "Move Partition” feature, allowing you to move the partition between the unallocated space and the target partition to make them adjacent so that you can extend the partition successfully. It doesn’t distinguish free space and unallocated, so you can extend a partition with free space or unallocated space.

Besides, it provides the ability to convert primary partition to logical without losing data, and vice versa. What’s more, with the ability to merge partitions, you can easily extend the partition in any case without losing data. You can download the Demo version for a free trial. It allows you to preview all functions and simulate all operations.

Let’s see how to extend volume on Windows server 2016:

Download Free Demo Server 2022/2019/2016/2012/2008/2003
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Step 1. Install and launch AOMEI Partition Assistant Server. In the main interface, right-click the partition and choose “Advanced” and select “Merge Partition”.

Merge Partitions

Step 2. In the pop-out window, check the adjacent partition or unallocated space to be merged.

Choose Unallocated Space

Step 3. Preview the partition layout. If it doesn’t meet your needs, you can just click Undo to go back to any step you want. When everything is perfectly checked, Click Apply to apply all the changes.


Most importantly, if there is no unallocated space on the hard drive, you can also directly assign some free space from one drive to another via the “Allocate Free Space” function.

Step 1. In the main interface, right-click the partition that has much free space (here is partition D) and choose “Allocate Free Space

Allocate Free Space Mbr Disk

Step 2. In the pop-up window, type the free space that you want to assign to C drive from D and choose C drive as the destination location. Then, click “OK”.

Allocate to C Drive

Step 3. Finally, click "Apply" to submit the operations.


In conclusion, with AOMEI Partition Assistant, you can easily extend a partition under any of the situations that caused to Extend Volume grayed out on Server 2019/2016/2012/2008/2003 or the latest Server 2022. Additionally, it provides many other useful features, such as convert to GPT/MBR disk without data loss, clone partition, clone Windows Server to SSD/HDD, quick partition, and so on.

If you want to install this software on an unlimited computer and manage disk partitions conveniently, you can try Unlimited Edition.  The Unlimited edition can Create Portable Version, which allows you to create AOMEI Partition Assistant on a removable device. 

Dervish · Staff Editor
Dervish is an English editor of AOMEI Technology; He is delicated to offering users easy and effecitve solutions for issuses related to disks and partitoins. In his spare time, he enjoy wathcning films, playing footable, traveling and so on.