Windows 10: Disk partition not recgonized by Win 10

I have a 3 TB disk partitioned into two parts. In Win 7 they had two different drive letters. Win 10 does not recognize the second partitioned portion of the disk and has labeled it unallocated. The disk manager provides no option to allocate the partition (most options are greyed out). Anyone have a solution or do I have to buy a third party disk management application?

:)

 

Removing redundant disk stops Win 10 from loading.

Have upgraded to Windows 10 which I like. When I remove redundant disk, Win 10 stops working 'til I replace redundant disk

Per Disk Management

Disk 0 is redundant drive I want to remove, shows as E: This originally had Win 7

Disk 1

Disk 2 has Win 10 programs, shows as c:

Disk 2 has 4 partitions. d: ; c: (Healthy, Boot, Page file, Crash Dump, Primary Partition); blank:Healthy Recovery Partition; f:

Disk 3

BIOS set to first boot from Disk 2

Background

Disk 0 was main disk using Win 7

Disk 2 a new drive bought at same time as Win 8 DVD install disks

Used upgrade feature of Win 8 (to preserve existing data) & installed Windows on Drive 2

Subsequently upgraded to Win 8.1 then Windows 10.

What changes do I have to make to my system so I remove redundant disk?

 

Windows 10 Anniversary Update error-!Disk Controller

See:
http://borncity.com/win/2016/07/18/windows-10-upgrade-disk-controller-current-active-partition-is-compressed/

 

See what this makes of it. http://www.partitionwizard.com/free-...n-manager.html

 

If that above doesn't do it there also this one below

Download Free AOMEI Partition Assistant Standard - Magic Partition Manager Freeware

 

I tried the recommended third party partition managers but they did not work. I pulled the HD out of the computer and put it in an HDD docking station attached to a Win7 computer. It seems like Win 10 wiped the partition clean and removed the drive letter. Win 7 had no trouble partitioning the 3TB disk into two parts (2048GB and 746.5GB). I cannot change this partitioning further more I can't use the 746.5GB section of the drive. More research needs to be done on this issue. The real problem is the 746.5GB partition had my music library. I can reconstruct it but not without a lot of work.

After further investigation into using an HDD over 2TB I found the problem to be a GPT protection issue with the lost partition. I found a way to remove the GPT protection through the use of the "diskpart" command. I was able to reformat the disk using GPT partition instead of MBR which is only good up to two GB HDDs. I could not save the data on the lost partition but it should not happen again.