HDM 16 Error - Deleting partition results in Disk not found. Can't provide more details because it happens after reboot. I suspected something was wrong becuase it said it needed to reboot to complete the task when it was a straightforward delete partition.

Tried it with HDM 15 and it worked in an instant.

HDM has real problems. The interface is terrible. How do you get a simple text list of partitions on a drive?