If you are trying to delete GTP or EFI partition on your hard drive under Windows Server 2008/7/Vista using management console are you out of luck. However, here is the easiest way to get around it:
Start command prompt and run diskpart.exe in command prompt issuing these commands as per illustration below:
d:\path>diskpart.exe
DISKPART> list disk
DISKPART> select disk x
DISKPART> clean
Please note, the reason for using ‘clean’ command instead of ‘delete volume’ is that ‘delete volume’ crashes diskpart utility when attempting to delete GTP/EFI partitions. Also outdated diskpar.exe utilitiy, which is frequently used for aligning physical partitions and is still quite popular for SSD optimization, cannot even read disk layout containing GTP or EFI partitions.
Great post: How to Delete GPT Partition or EFI from Mac Hard Disks In Vista or XP
Reference: A Description of the Diskpart Command-Line Utility
Diskpar & Diskpart in server environment: Disk Partitioning Offset
Disk partitioning Alignment: Disk Partition Alignment Best Practices for SQL Server
SSD Optimization guide: OCZ Technology Forum
