I had the same issue, I tried editing the VM but it wasn’t letting me save it. So I tried the following:
- Tried editing the VM to change RAM/CPU etc, but it wasn’t letting me save it
- Deleted the vm (not the data) and tried adding it again, didn’t fix it
- Tried moving the vbox file to another directory and import it, but it didn’t let me move the vbox file so I realized there’s a virtualbox process running that’s holding a lock on it. So I killed that process and started it again and my VM booted