Thanks for the reply.

Didn't try safe mode. Will try disk maintenance access in safe mode.

Unfamiliar with ATI/Disk Director. Again, this is not a primary boot drive issue - new 900 Gb SSD is...

Just cloned Windows 10 system disk from 230 Gb SSD to 900 Gb SSD using Acronis. New system drive works fine. Trying to remove the OS partition from old OS drive and get "OS (E:) Simple Volume is...