virtualbox.org

With Windows 8.1 Pro host I had no problem creating and using 64bit clients. I upgraded the host to Windows 8.1 Enterprise and all my 64bit clients stopped working immediately.

A problem, I figured that might be related to the Pro->Enterprise upgrade. So I decided to install Enterprise cleanly instead.

I formatted the host, did a clean install of Windows 8.1 Enterprise. Clean install of Visual Studio 2013 (with Windows Phone 8 emulator). Immediately installed VirtualBox. Again I find I am not able to add 64bit clients: the OSes are not listed in the drop down box.

The BIOS has not changed. I still have visualization support turned on. Worked fine on the same hardware with an otherwise identical Wndows 8.1 Pro setup. I am wondering if Visual Studio is stealing and messing up visualization on 8.1 Enterprise in a way that it did not do on Pro?

Any ideas?

IIRC the Windows Phone 8 emulator attaches to VT-x/AMD-v and that makes it unavailable to VirtualBox. No hardware acceleration means no 64-bit guests.

Also, the Enterprise version includes Hyper-V by default so that would have to be disabled.

Thanks for the info.

My Enterprise install does not allow 64bit clients in VirtualBox - even straight after the host has been rebooted - when Visual Studio has not even been run. Visual Studio must be very aggressive to steal these abilities without being run.

I will hunt through Visual Studio looking for the options I need to turn off. Thanks again.

some info:
http://www.eightforums.com/tutorials/42 ... s-8-a.html