Then, in the second tab, scroll to the bottom of the list and enter "Advanced tasks".

Here is the list of Advanced tasks (updated on June 01,2018):

 - Fix the video categories…
 - Remove duplicates…
 - Remove empty elements…
 - Analyze undetected episodes…
 - Diagnose the server side of the collection…
 - Reactivate the groups…
 - Sort the videos…
 - Client side collection diagnosis…
 - Force search for all files...