There are certain incidents that are caused by users (teachers) deleting unconsciously some course files. Currently the only way to guess that a user has deleted a file is to explore web server logs and it's really imprecise.
This patch (against 1.9.4) introduces a log each time a user tries to delete a file or directory. It stores who deleted the file, what course, when, the file he/she tried to delete and if the operation has been successful or not.
To see file deletion attempts:
WHERE module='files' AND
Thanks for your time