Hi Nick, I've never had this issue before until last night. When exporting my new mix, I can see the video freezing (during export) and thus the exported mov also freezes during playback. None of the videos in the mix freezes during my set. Also I tried to export the file again, paying attention to the parts that were frozen...and those parts were ok during export but now other parts are freezing. Videos are from recommended sites. I can send you the files and also a link to the exported mov.
