did you do the last step … Factory Reset ?
There’s been lots of ideas suggested for the MP4 fix … the only one that works in most cases is “remuxing”
(this is a quick process and you don’t lose and quality) … if you wan’t to keep them MP4 then use
My MP4Box GUI : http://www.videohelp.com/tools/My-MP4Box-GUI
also you can use MKVMerge (included in MKVToolNix)… but this will remux to MKV container
