Oracle VM VirtualBox supports executing the VBoxSVC in Windows session 0. This allows VBoxSVC to run like a regular Windows service, which in turn enables headless VMs to continue running even if the user logs out.
This is currently an experimental feature.
The feature is disabled by default and can be enabled by creating
a REG_DWORD value ServerSession0 in the key
HKEY_LOCAL_MACHINE\Software\Oracle\VirtualBox\VBoxSDS
of the Windows registry. Specify 1 as the
value's data to enable the feature, or 0 to
disable the feature. A host reboot is needed in order to make the
change effective.
Due to different Windows sessions having their own set of resources, there might be some issues with accessing network shares created in the interactive user session when at least one of the Oracle VM VirtualBox processes are running in session 0.
For accessing network shares within session 0, a possible workaround is to establish permanent access to the share and then restart the host.