Sorry, I took that to mean you had one 3 TB hard drive but just wanted to make sure you did not have another one. The fact you were asking about another drive confused me.Yes Only 1 Hard Disk (stated in my very 1st post)
Possibly Windows 10 is just not compatible with that configuration. There may be some info on the Acronis site...Can you create a partition on the unallocated space on Drive 0? NO it is inaccessible