Installing Win 8.1 64 to 3TB Disc

Hello,

I've come a little unstuck here as have done something I've never done before - I've built a PC with a 3TB and 2TB drive. I want to partition the 3TB drive to have a 1TB C Drive and 2TB D Drive. The C drive will look after the OS and program files. The D Drive will have all user folder items (Docs, Pics, Music, etc) mapped to it. The additional 2TB HDD will be set to be a back up drive for the D drive so if one fails, all user specific data is still intact regardless of which drive fails.

The problem I have is installing the OS to the 3TB drive. When I create a 1TB C drive partition, the OS installs fine but in Windows, once it starts, in disk manager, I get the following:

350MB System Reserved
C 1071.09TB
976.56 Unallocated
746.52 Unallocated

On the 976.56 unallocated, I can right click and the option is there to create a new simple volume. There are no options available (all greyed out) for the 746.52. I really need to get these two as one partition but can't see how to do it.

Apparently it has something to do with GPT against MBR, but I cant see anyway of activating this in the start up install of Windows 8. I've drawn a blank other than this on Google and am scared of making a hash of this, hence my asking (in desperation) for some help or pointers from people who know far more than me

Please can anyone help, I'd be most grateful for any and all advice

iirc it is probably because you are installing/installed Windows in BIOS mode and not UEFI (or, of course, yourmobo doesn't support UEFI anyway), so the installation will automatically prepare as MBR.

You'd need to make sure the BIOS boot mode is UEFI then install Windows and create the partitions during the install and it should automatically turn it into a GPT disk when it detects it is over 2TB.

I think this is only because it is the OS drive, if it was a purely data drive you could use it as GPT no problem even with a BIOS mobo.

Alternatively try this, which might allow you to get round the problem "as-is": http://knowledge.seagate.com/articles/en_US/FAQ/2186... (may be a similiar utility from whoever makes you HDD)
And also see: http://support.microsoft.com/kb/2581408

A google search for "install windows 3tb drive" should yield more.

If your BIOS does support UEFI and you have only just installed I'd be tempted to re-do it again and get it right at install time rather then relying on device drivers to fudge it.