Off the top of my head, I would tell you to go back into disk manager and right-click the free, unpartitioned space in the spare drive. There should be a format option as well as a drive letter ...

You may view your hard drive in Disk Management and see unallocated space. The space will be on the hard drive, but Windows cannot use it. It is like having a spare room in your house but locked off.

An Unallocated disk or drive is one that hasn’t been assigned any drive letter. To install an operating system on brand new hard drives, you will be required first to partition it because you can’t ...