You have a Windows 2012 R2 server virtual machine with multiple disks that is formatted with the ReFS file system and you have just one of the disks at the hypervisor level then proceed to extend it within Disk Management:
Attempting to complete the Extend Volume Wizard throws the following error:
There is not enough space available on the disk(s) to complete this operation.
The expansion of the disk fails. You attempt to use diskpart but receive the same error:
Virtual Disk Service error:
There is not enough usable space for this operation.
You attempt to expand the disk by 1MB but the results are the same:
I’m not sure whether this is a bug in the earlier versions of Windows 2012 R2 and ReFS but expanding the disk by 1000MB completes successfully:
10000MB also works:
Sames goes for 100000MB:
With 52.60GB of Unallocated space left, leaving the Select the amount of space in MB as the default (maximum) completes successfully: