I was able to make this work by making vboxclient systemd service to run in user namespace and depending (via WantedBy) on graphical-session.target. Here is the configuration which worked for me (with also a service for clipboard sharing):
I was able to make this work by making vboxclient systemd service to run in user namespace and depending (via WantedBy) on graphical-session.target. Here is the configuration which worked for me (with also a service for clipboard sharing):