Is my Core 2 Duo not supported anymore by latest VirtualBox?

[labya]

I have a Core 2 Duo processor. VirtualBox 5.2 works fine. But VirtualBox 6.1, it won't start any VM anymore (doesn't matter if existing or freshly created). As you can see in my picture, it complains about "enabled hardware virtualization" and tells me to disable it in System - Acceleration tab. The problem is, you can't disable anything there. Even if you set the drop down box to "none" and uncheck the checkbox, the GUI keeps complaining and won't let you save the settings! The OK box stays greyed out. Same behavior on both Windows 10 (host OS) and Arch Linux (host OS). Is this "just" a GUI bug (bad enough), is this bug know yet and will it be fixed very quickly, or has the Core 2 Duo been abandoned because let's assume VirtualBox now REQUIRES hardware virtualization (a nightmare) and they haven't updated their GUI accordingly ?

[scottgus1]

Virtualbox 6.1.x no longer allows running guests without 'virtualization technology' (VT-x). 6.0.x still allows non-VT-x hosts.

So if you want to keep that Duo running Virtualbox you'll have to stick with 5.2.x or 6.0.x. 6.0.14 was stable and my regular workstation is still using that version.

And yes that error message has thrown a few folks for a loop...

[mpack]

It would help if you told us the exact CPU model number: my old Core 2 Duo had VT-x, I believe most variants did.

The Core 2 Duo didn't have extended page tables and a few other things, which will impact performance - and always did, even before v6. But it won't stop the VM from working at least as well as it ever did on this host.

IMHO the most likely reason of your symptom is that VT-x is disabled in the host BIOS. It's available but you never enabled it because VirtualBox had an option to run without it, provided you restricted yourself to 32bit guests. This is the option that has been withdrawn in v6, because it isn't worth the developer man hours to keep it going for no good reason.