MATLAB: Am I unable to launch MATLAB after upgrading to OS X 10.8 or later

MATLAB

After upgrading to OS X Mountain Lion, or OS X Mavericks, or OS X Yosemite, I am no longer able to start MATLAB. It either completely refuses to launch without any errors, or it shows the error "MATLAB cannot be opened because of a problem".

Best Answer

When MATLAB fails to start-up correctly following a major Operating System (OS) update, the issue is usually caused by a change to the OS's Windowing System or a change to your computer's MAC address configuration. Both of these issues have been known to pop-up following an update to OS X.
For MATLAB R2013b and higher, do not perform the steps below, contact MathWorks installation support instead.
For releases of MATLAB prior to R2012b, MATLAB used 'X11' as it's primary Windowing System, which has since been replaced by XQuartz.  As a result, whether you did an upgrade on top of your existing OS X or if you did a clean installation you will need to reinstall XQuartz for MATLAB R2012a and below. XQuartz can be downloaded from here:
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If MATLAB isn't able to open after reinstalling XQuartz, the issue may be Java related. For MATLAB releases prior to R2013b MATLAB requires Apple's Java 6, which can be downloaded from here:
Once it is installed you should be able to launch MATLAB. However, if you are still having issues, please contact MathWorks installation support.