Are you using a Mac running Mountain Lion v10.8.4? If so, then Blackboard has released a special app called the "Collaborate Launcher for Mac" which is now required for Mountain Lion v10.8.4 and later. From Blackboard: For Mac users who are on Mountain Lion (v10.8.4 or greater), Blackboard has made a major change to the way Collaborate sessions are launched.   Mountain Lion users must n…