Hi Since upgrading to OS Sierra, iTunes constantly crashes. I cannot restart my Mac-mini (2012) without physically holding the power key to get it to shut down as iTunes prevents it from shutting down even after using 'force quit'. I have reinstalled iTunes & reinstalled Sierra, but the issue still reoccurs. I've been trying to fix this for weeks now with no improved results. After I manually reboot, I am able to open and use iTunes, but if I leave the application open and idle, it crashes 'app not responding' and I am back into the above cycle. Please help! Thank you Kristian Gunn PS - Tried restoring to factory settings method also!