Windows 10 8TB HDD only showing as 2TB


New Member
I have a brand new Seagate 8TB Barracuda drive. It show the correct model numberin the device properties window (ST8000DM 004-2CX188), but in Disk Management, it only shows size as 2048GB.

This is the second time I connect the disk, and the first time it showed all 8TB, so I'm not sure what the hell is going on. I formatted it in windows as NTFS, then connected it to my mac (moving from mac to win again) - Mac wouldn't recognize it, even though I had NTFS support installed, and asked me if I wanted to initialize it, to which I said "Ignore".
When I connected it back to the Win computer, it was down to 2TB. I'm sure it has something to do with the Mac. I know this isn't a mac forum, but maybe someone has some idea as to what may have happened. Mac shows NO partitions, neither does Windows.


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Cloud Security Engineer
Staff member
You have the disk set up with MBR rather than GPT. The older legacy MBR only supports 2 TB partition sizes.

In Windows you can (from an elevated command prompt) type diskpart
list disk
select disk #
(# is the 8TB disk)
convert gpt

This will destroy any data


New Member
Found the problem 🤦‍♀️

I was using an external dock, and my oh-so-smart 25+ years sys admin husband failed to tell me it supports a maximum of 2TB :applaud: