We are currently having an issue where the VM does not always boot as there are some VBox services running which even admin cannot stop.
It seems to occur if the VM has not been shut down cleanly by the previous user. It's become a bit of a nightmare as our VMs are often used in back to back lessons.
The next user runs the batch file to launch the VM and it either closes without doing anything or hangs waiting for the VM to finish doing something which can take 15 minutes.