In step 3 when you reset the courses, did you select Delete all submissions under Assignments?
How Moodle's garbage collection works?
Yes, checked all fields and Delete all submissions under Assignments/quiz/forum from all the courses.
Still files are exist in moodleData folder and related info in database (mdl_files).
What I guess is , even though I runned cron job several times, the scheduled task for deleting 'orphane file' is not running.
Anybody knows about that schedule task? What is the name of that scheduled task or how to run?
Thank you very much.