We've seen this happen if you have a large number of EmuMovies downloads. The way EmuMovie API works is if there is ever a 5 minute window where we don't download from them after asking for a media URL all the URLS go bad and we have to ask for new ones. Tryin to do so on a queue as large of yours is extremely difficult and time consuming, and if we DO get responses it typically takes longer than that 5m window allows and you get stuck in an infinite loop. For now what I would suggest doing is downloading all the media you need from LaunchBox's Games Database then once that queue is done downloading, use EmuMovies to fill in any gaps. This should help.