MATLAB: Matlab 2015b frequently gets frozen (not responding) on mac os yosemite

frozenMATLABmatlab2015b

Hi I installed matlab 2015b student version on my macbook(OS yosemite) a month ago. And recently i found it frequently gets frozen while i am using it. I force quit it, and reopen it, then it will stuck on start. i have to restart my mac in order to use it. So i am wondering if the mathworks team can help me solve the problem.