Hi all. I am on a mid-2011 27" iMac running Yosemite 10.10.1, I have a 3.1 GHz Intel Core 5, 8GB memory with 3 external drives. Since going from Mavericks to Yosemite, I have had nothing but problems with iTunes intermittently starting/stopping. During this, my hard drive crashed and it was replaced at my local CityMac store. Anyway, I've tried disabling WiFi, DropBox, Google Drive, iCloud, I've tried turning off Genius and Match, I've tried reinstalling, I've even copied my playlist over to the hard drive (it is on one of my external hard drives) all to no avail. All other applications seem to work, although I've been getting the spinning beach ball more than I care to since the hard drive was replaced. My hard drives are functioning normally. I've repaired disk permissions in Safe Mode and reset PRAM as well. I've been all over the Apple forums with no answers. Any suggestions are much appreciated as I am very frustrated with this issue!