Logic Pro X/Mainstage Sample Rate error

Hello, ever since I upgraded to Yosemite, I've been having this Sample Rate issues with Logic and Mainstage. With Mainstage It once failed me on an important gig where all the sounds where out of tune. Apparently I didn't know it was a Sample Rate issue so I had to toggle between 44.1 and 48 Hz. The problem is that I don't know *** it's really happening. I use a M-Audio M Track interface as my input/outputs for both Logic and Mainstage. In Logic the problem comes when I connect my Studio Monitores obviously on the M-Track outputs for monitoring. In Logic the problem is far worse cause suddendly al my mix starts to clip and slow down and all the pitch of the mix starts to go down and a message saying something like "Logic detected a sample rate of 38.1 or 40.2". I really need a solution for my problem. I later find out that my interface records on 48 Hz while my projects are always on 44.1 but I didn't know this 'till today. And I doubt that that was the problem since this never happened to me on Lion, Mountain Lion and Mavericks using the same Logic and Mainstage, and the same interface...