I have the newer Mac Pro and ever since upgrading to Yosemite, my Apple Mail program is terrible. I can restart and get Mail to send and receive, and then after a while it gets "stuck" again and I have to restart to get it to work with my Yahoo! Business Mail. It can't be a Yahoo issue since my iPads and iPhones connect with no issues. Anyone else seen this or know a fix? This is driving me nuts!