I’ve started playing with virtualization using Oracle VM VirtualBox Manager and Ubuntu 20.04.6 but I faced some trouble. When I try to add new VDI to my vm inside Storage setting as a IDE Controller (alongside the Ubuntu’s optical drive) and run machine, I am asked for Ubuntu reinstallation. But when I remove this VDI (Zajecia_4) from IDE Controller- I am not asked for reinstallation. Below, I attached the option I chose for VDI, optical drive and boot order’s option.

Did I miss something during configuration my VM? Or maybe reinstallation is expected behaviour in this scenario? What should I pay attention to when looking for errors in the logs?

Thanks in advance for all the answers and tips!