why does my iTunes freeze after periods of time

So i have a MAC Mini with an external hard drive. For some reason after about 15 mins. the itunes will freeze up and i have to remove the external hardrive and plug it back in and then everything works fine. But this is a pain in the butt, because i recently got apple tv and i like streaming stuff off my itunes to my tv. But i have to keep getting up and unplugging the external hard drive and pluggin it back in so my itunes will work properly on the mac mini. This is quite frustrating. Does anybody have an idea or Clue as to why this is happening?

Not sure if this is related to it, but i have "time machine" for my external hardrive and that seems to fail backing up sometimes as well. but when i un plug it and plug it back in the back up works flawlessley. Could this all possibly be related to the external hard drive.

Thank you for any and all feed back 🙂

also im tired of having to force quit itunes when all this is happening.