In this article, I will solve the below Windows Server Issue

Error extending volume: Size Not Supported

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Scenario

When I tried to Extend Volume for a specific drive in Windows Server 2012 R2 by opening

• Server Manager > File and Storage Services.

• Navigate to Disks > (I have unallocated free space (19.5GB)).
• Right click on C Drive > Select Extend volume.

• The following dialog will be shown to set New size.

• When I set the New size and clicked OK, I got “Extend failed” as shown below:

• I clicked on Extend failed to find out the reason, I got

Error extending volume: Size Not Supported

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Cause

The “Error extending volume: Size Not Supported” usually occurs because of there is a partition/drive between the original partition and the unallocated space. Thence, 

If you want to extend volume, you should make sure that there is no partition between the original partition and unallocated space.

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Solution

In this case, you will need to unallocated the drive space beside the operating system drive. but this means all data in this drive will be deleted!

So before you getting started,  you should

• Make sure that the unallocated space is greater than the F:\ drive (the drive beside OS drive) size to ensure that you can move the F:\ drive content to this space.
• Create a new volume from the unallocated space.

• Move the data files from F:\ Drive to the New Volume.
• Delete F:\ Drive.

• You are now having unallocated space beside the Operating System drive.
• Again, try to extend the Operating System drive that should be now extended properly.

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Applies To

• Windows Server.
• Windows Server 2012.
• Windows Server 2016.

See also

How to extend a volume via Disk Managment in Windows Server 2012.