currently using fedora 5.13.12-200.fc34.x86_64. am experiencing the same issue with 3 VM app.
Oracle Virtual Box
I can start all 3 app and start the the process of creating new VM… however as soon the installation completes and reboot the VM i will get message like “virtual machine not responding”. the VM is configured with 3 CPU; 8GB RAM; 30GB disk.
thanks for reverting… and apologies for the delayed reply. was kinda busy for a few days.
after the recent update… it seems to be working again. I didn’t do anything at all to the settings.
thanks again. hopefully it stays this way.