Why Has Movie Maker Never Worked in 6 Year?

My son's been playing hockey for 6 years. I used WMM back when he was a Mite and I remember putting together movies into the wee hours, taking hours to get the cuts right, and then BAMOO, couldn't save, clips would show up as exclamation points, or the preview would disappear. Every season, every year, it is the same thing. I moved to new hardware, new operating systems, XP, Windows 7, Windows 8, Windows 8.1, and yet I have problems with every version of the OS and every version of the "Essentials" Movie Maker, Today, it is stopping while saving the movie at 47%. The project is trashed, it can't be saved. It's about a 2 minute clip of a great game where my son scores the team's second goal. He's now a Peewee and his game has made many improvements over the years. If he played like Microsoft Movie Maker his coaches would have given up on him and thrown in the towel. I'd still support him, of course, because he's my son. I've tried all sorts of help for WMM over the years. I've sent in file after file of debug code, debug traces. By now you'd really expect that someone could just have rewritten the entire code base from scratch. In fact, I've been using another tool, albeit not free for about 3 years now because this "tool" is so unreliable. Please, please, please, stop allowing people to download this application. If you can't get it right after 6 years, can you please let it go?