virtualbox.org

I'm trying to find out why in VirtualBox?
1. Processor Acceleration tab is always "grayed-out" for all VMs
2. I cannot install or run Windows 10 32-bit in a VM

VirtualBox reports "this pc's processor doesn't support a critical feature (NX)" when attempting to upgrade or clean install Windows 10. My immediate concern is in wanting to upgrade a Windows 7 license to Windows 10 activation before the deadline.

I do have Windows 7 32-bit running successfully in a VM. Although it does start with a "VT-x/AMD-V hardware acceleration is not available on your system" dialog.

Host:
Windows 10 Home 64-bit on an older Lenovo Core II Duo (M55e) desktop
Hyper-V Virtualization is enabled in firmware (as indicated by system info)
no virtualization settings are available in the BIOS

Guests:
Windows 7 Home Premium 32-bit and Windows 10 Home 32-bit
VirtualBox 5.1.2r108956 with Guest Additions 5.1.2-108956
Processor PAE/NX is enabled
Hyper-V Paravirtualization (as indicated)
Acceleration tab is always grayed-out
tried Windows 10 install both with and without the Guest Additions installed

Any insights or suggestion appreciated.

Use the Windows 10 template when creating a Windows 10 guest. That will ensure that all required processor features are enabled.

Note that Windows 10 32bit (as a VBox VM) requires VT-x/AMD-v, as in fact was the case with Windows 8.x.

The following link provides related information :-
FAQ: I have a 64bit host, but can't install 64bit guests.

Thanks for the quick response and thorough explanation @mpack.

The old computer fails step 1 of the link's checklist. No VT-x capability confirmed with the "VT-x/AMD-V hardware acceleration is not available on your system" dialog when creating a new VM.

There are also no 64-bit choices for creating a new VM with any modern OS. So that fails step 3 and this seems to be a lost cause.

But two basic (dummie) questions for some understanding:

1. Why does Windows 7 (32-bit) work in a VM?

2. Why Windows 10 works natively on this computer while it will not in VirtualBox?

For all Windows newer than Win 7 Virtualbox needs VT-x to run the guests because of CPU features used by the (guest) OS.

But why is it required when Windows 10 runs natively?

Very simplyfied: Windows 10 uses so much of the CPU (features) that Vbox needs VT-x to provide all these also inside the virtual PC.

dlfuller wrote:But why is it required when Windows 10 runs natively?

Virtualizing a CPU feature is not the same as using it natively. It might be technically possible to virtualize at least some of these features without requiring VT-x, but the number of systems that would be helped by this is so vanishingly small that the devs don't consider it a worthwhile use of their resources. VT-x has after all been a part of nearly all 64bit CPUs for almost a decade now.

BTW, can you please tell us your exact CPU model? Googling tells me that the Lenovo M55E used a Core 2 Duo E6300 CPU, which does have VT-x according to Intel.

In fact you really ought to have provided a VM log right away: pick any VM, and with the VM fully shut down, right click it in the GUI. Select "Show Log" and save "VBox.log" (ONLY) to a zip file. Attach the zip here.

Thanks for the follow-up.

The M55e is type 9645 and CPU is a E4300, not E6300. From what I could find Intel specs state no VT-x.

A log file is attached.

Yes, that seems to be correct, i.e. no VT-x for your CPU. For future reference the Intel specs for the Core 2 E4300 are here.

Well, I'm afraid that's terminal. While other VM platform requirements may vary, VirtualBox requires VT-x for all 64bit guests, for all Windows versions since Windows 8.0 (including their 32bit variants), and I have no doubt will increasingly require it for all modern guest OS's.

I thank you for the thorough check and explanation (bad news).

It looks like some E6xxx CPUs could be used in the M55e to get VT-x,