The difference between /mnt/user and /mnt/disk or cache has been an ongoing issue for several years now. Some versions work better than others, theoretically the 6.8.x tree was supposed to have solved all that for good, but apparently not.   Initially the /mnt/cache path will not exist with no cache set up, but the docker engine will happily create defined paths as soon as a container with that path defined is started.   There are no guaranteed paths with direct disk access r