I have this problem.
I login remotely to a machine with Virtualbox installed by launching:
ssh -Y root@virtualbox
After that, I launch a Virtual Machine:
nohup VBoxSDL --startvm vm1
or
nohup VBoxSDL --startvm vm1 &
After that, I don't have the prompt anymore.
Then, if I switch off my local machine, the virtual machine goes down (no matter whether I use & or not).
How can I keep it running after I switch off my local machine?