virtualbox.org

platform:
'old' intel server board, 2 xeons, 16gb ram, 1 TB test drive - passes platform compatibility check

Have installed windows 2012R2 as native OS
intel VT is enabled in bios
installed VB v 4.3.16 r95972

When I try to create a new VB guest, the only windows options offered are all 32-bit and 2012 is not listed. The User manual says it is possible and this forum is alive and well with many topics related to 2012 as a guest.

Do I simply select "Other" or ?

If you do not see any 64-bit OSs, you probably do not have VT-x enabled. You must have hardware virtualization to run a 64-bit OS in a guest.

I noted in my original post VT was enabled. I double checked that on a reboot.
Bios setup > advanced > Processor configuration > Intel Virtualization Technology [Enabled]

About the only thing not enabled on that page was "Simulated MSI Support"

Intel says:

Intel® Virtualization Technology (VT) must be enabled in the BIOS before Microsoft* Windows Server 2008 64-bit edition is installed. Microsoft* Hyper-V server role is only supported with 64-bit supported hardware and operating systems. Only then can Microsoft* Hyper-V server role be added.

I created a Hyper-V server, so am assuming VT has to be running properly and obviously in 64-bit mode since 2012 requires that.

If you are seeing 64 bit options for guest OS, then I must have some other condition/settings blocking it on mine.

======================= update =======================

On a hunch, I decided to remove hyper-V to see if it might be interfering with VirtualBox. That was no easy task. Fortunately I stumbled on a how-to tip, to use a command in PowerShell: which worked like a charm.

With Hyper-V gone, I opened VB Manager and voila...several 64-bit OS options are listed, including 2012 . Seems VB is limited to 32-bit OSes if Hyper-V is present.

BugMagnet wrote:I created a Hyper-V server

That's your problem right there. Hyper-V is locking the VT-x capabilities of your host and doesn't allow any other programs (like VirtualBox) to use it. You have to disable Hyper-V. For more, please read: I have a 64bit host, but can't install 64bit guests.

thanks for that tip socratis...I had already removed Hyper-V by the time I saw your reply, but the link you gave has some additional information about other potential blockages. Good to know.