The real system requirements? Cannot run VirtualBox VMs on Core 2 CPU.

[Nickolai]

I have tried running VirtualBox 5 on Ubuntu 16.04 LTS on three machines with Core 2 CPUs (specifically, E7300, L7500 and L9400). On all three machines I have attached Ubuntu 16.04 LTS ISO as a boot device to install Ubuntu as a host OS. On all three machines this resulted in VirtualBox crashing in the same way: it displays a dialog box saying

Guru Meditation
A critical error has occurred while running the virtual machine and machine
execution has been stopped.
[...]
Press OK if you want to power off the machine of press Ignore if you want
to leave it as for debugging. Please note that debugging requires special
knowledge and tools, so it is recommended to press OK now.

at which point the whole graphical desktop hangs and I have to switch to console and kill VirtualBox via htop.

I suspect that these systems do not pass some unspecified system requirements. If so, what are they, exactly? I thought a CPU with VT-x would suffice, at least. While E7300 doesn't have VT-x, L7500 and L9400 do.

Here's the logs (also attached, zip'ped). Here's the screenshot (it's pitch black):

[socratis]

Please ZIP and attach the log locally. Not a lot of people (including me) will go to 3rd party sites.

[mpack]

VirtualBox does run on Core 2, in fact I was running VirtualBox on a Core 2 duo myself until very recently.

[Nickolai]

Please ZIP and attach the log locally. Not a lot of people (including me) will go to 3rd party sites.

Done.

VirtualBox does run on Core 2, in fact I was running VirtualBox on a Core 2 duo myself until very recently.

Good to know. Now, the question is, how to do I make it run?

[mpack]

Good to know. Now, the question is, how to do I make it run?

For an answer to that question, please visit the Ubuntu forums. This site is only for VirtualBox users.

VirtualBox VM 5.1.38_Ubuntu r122592 linux.amd64 (Jul 10 2018 10:40:22) release log

That means it's a knockoff, not VirtualBox.

[Nickolai]

VirtualBox VM 5.1.38_Ubuntu r122592 linux.amd64 (Jul 10 2018 10:40:22) release log

That means it's a knockoff, not VirtualBox.

You mean it is a version of VirtualBox provided by Ubuntu and not supported here?

[socratis]

It looks like you're using the distro's fork version of VirtualBox. You can either ask in their forums for help, or completely remove/uninstall/delete/purge their version and install the official version from the Downloads section of VirtualBox (https://www.virtualbox.org/wiki/Downloads).

00:00:01.364440 HM: HMR3Init: Falling back to raw-mode: VT-x is disabled in the BIOS for all CPU modes
00:00:01.690395 Full Name: "Intel(R) Core(TM)2 Duo CPU L9400 @ 1.86GHz"

In any event, you're going to have to address the absence of VT-x in your BIOS. Your Core2 Duo L9400 supports VT-x, so it's a matter of enabling it in the BIOS. See your PC's manufacturer help on how to do this.