It's not going to be missing the next time around. Usually the file is missing due to some concurrency-problem where the file only gets to exist a little later. A process restart certainly fixes this.

If the problem persists, a larger part of the supervision tree is restarted. This eventually leads to a crash of the full application, if nothing can proceed without this application existing in the Erlang release.

The key point is that there's a very large class of errors which is due to the concurrent interaction of different parts of the system. These problems often go away on the next try, because the risk of them occurring is low.