I've come to this crap thread to report a crap event. Retarded Redditors have redirected my question at https://web.archive.org/web/20250309041755/https://superuser.com/questions/1885073/i-only-have-the-last-half-of-an-mp4-file-how-do-i-play-it to https://superuser.com/questions/538829/how-to-repair-a-corrupt-mp4 (the live version of question #1885073 redirects to question #538829).