Thanks for the question, and welcome to Apple Support Communities.
I understand you are having some issues with iTunes on your Mac. You may want to isolate the issue further by testing to see if it persists in a new user account:
You can also try starting iTunes in safe mode:
Thank you for using the Apple Support Community. Due to the nature of your issue or question you may find more information by using another one of Apple's support resources - https://expresslane.apple.com/GetproductgroupList.action
- Matt M.