virtualbox.org

I have currently installed VirtualBox on a new Windows 10 PC using Windows 10 build 19041 (Version 2004, May 2020). Trying to install Ubuntu 20.4 LTS in a new virtual machine, I consistently got this error. Eventually, I traced the problem to the Windows 10 setting "Kernisolierung/Speicherintegrität". Please forgive me that I have given the German name, but my PC is configured as German. I think that the English translation is "Core Isolation/Memory Integrity". Turning this off solved my problem. I could then install and run Ubuntu without further problems.

Thanks for your experience DaSi! "Core Isolation/Memory Integrity" is known to turn on Hyper-V, which most of the time impedes Virtualbox, for now. See I have a 64bit host, but can't install 64bit guests, post 2 & 3.