Blackboard Collaborate Launcher can be downloaded here
Use the following steps to download and install the Blackboard Collaborate Launcher:
On the Room Details page, click Join Room or, in the Recordings table, click a recording link. Blackboard Collaborate prompts you to download the launcher installer if you have not installed the launcher or if your browser "thinks" you have not installed the launcher.
Actual first time user: If this is the first time you are using the launcher, click Download.
Apparent first time user: Even if you already installed the launcher, you may be treated as a "first time user" and be prompted to download the launcher. This can happen if you cleared your cache and cookies last time you exited your browser, use secure or private browsing, or use a different browser.If this is the case, you do not need to re-download the installer again. In the First time using Blackboard Collaborate? pop-up window, click Launch Blackboard Collaborate now to bypass the download and then open your .collab file.
Your browser may ask you which application to use to open the ZIP file. If so, select the Archive Utility in System/Library/CoreServices. If your browser also prompts you to open the .collab file, do not do so until you have installed the launcher.
Open meeting.collab to join your session or play.collab to play your recording. If you don't see a prompt to do so, open the file in your Downloads folder.