virtualbox.org

have no such problems before, on same machine running XP and present 8.1 - W10 etc worked flawlessly - before that,

downloaded official W8.1 (32 bit) VM there, host is 32 bit too -
en-us/microsoft-edge/tools/vms/

and 2 different W8.1 (32 bit) installers - official site ISO and official DVD ISO -
en-us/software-download/windows8ISO

all these images refuse to start telling I use to have VT-x/AMD-v turned - wtf, what VT-x/AMD-v on 32 bit hosts? it never was there, they are 64 bit only present. used both latest 5 and 6 VirtualBox - same, have no idea what happens.

Have you upgraded Virtualbox to version 6.1 ? Hardware virtualization is required to run this version. There is no fallback to emulated mode for 32-bit guests.

Only version 6.0 or earlier can run 32-bit guests without hardware virtualization in the host PC.

BillG wrote:Have you upgraded Virtualbox to version 6.1 ? Hardware virtualization is required to run this version. There is no fallback to emulated mode for 32-bit guests.

Only version 6.0 or earlier can run 32-bit guests without hardware virtualization in the host PC.

no, I used only 5.x and 4.x - v6 is 64-bit only, my host machine is 32-bit

it does standart PAE/NX (Pentium 4) but there no way for VT-x/AMD-v as it 64-bit processors only

earlier it was ok to run both w8.1 (32-bit) and w10 (32-bit) in guest VM, don't know what happened now - may be it was different VirtualBox version, can't figure - tell me what VirtualBox version to install, I will make video with logs

I missed the 32-bit OS in the host! (That is logical for such an old PC I guess). I can't really help you there. I don't have one of those any more. I do know that even version 6.0 is not supported on 32-bit hosts, so no point in trying anything newer than version 5.2 .