Launch Failure.

So i need some help, every single time i turn off my computer and turn it back on be it from having to restart or shutting down for the night ect ect if i want to play league again i have to open the launcher hit settings and repair it, scanning all 6000+ files every single time. I would really like to know why this is happening and if anyone knows how to fix it since it is a colossal waste of time and extremely annoying. Thank you.