title: android studio can't open any projects or files in mac
body: <p>I am using the latest Android Studio version 1.2.2. I can't open any projects or files suddenly. It only show the "no files are open" page. Most of the tools are grey.</p>
  
  <p>I tried create a new project. The new project created successfully, but still stay in this "no files are open" page.</p>
  
  <p>Please give me some suggestions. Thanks a lot.</p>