
You wont be able to extend your C: with D: on the same drive. Disk management of Windows Client OS or Server OS is not a perfectly partition managing tool, it has some limitations.

Shrink Volume grayed out in Disk Management Reason of Shrink Volume greyed out. Right click on it and you will find the 'Extend Volume' greyed out. There are C drive, D drive and unallocated space on the Disk 0.


Why extend volume greyed out Launch Windows Disk Management snap-in.
