To re-run activation for MATLAB versions between R2008b and R2013b, you will need to delete your current license file, remove the MATLAB activation folder, then re-run the activation executable. The license file can be found in the following location:
(where $MATLABROOT is the installation folder for MATLAB on your machine)
On Windows it's C:\Program Files\MATLAB\R2008b Student\licenses\license.dat
On Mac you need to control click on MATLAB in your applications folder and choose "show package contents" then clear any files from the licenses folder, and remove activation folder.
On Linux it's /usr/local/MATLAB/R2008b Student/licenses/licence.dat
Once this file has been removed, delete the "activation" folder found in the $MATLABROOT directory. When this is done, you can rerun the activation client. To do this, follow the directions below:
Navigate to $MATLABROOT\bin\win32 and run activate_matlab.exe
Move into $MATLABROOT/bin and run activate_matlab.sh in a terminal
For Mac OS X:
Open a Finder, and locate the Matlab.app. Double-click the application to invoke the Activation client.
If you are not prompted to reactivate MATLAB, you can also activate by uninstalling and reinstalling MATLAB as well.
Be sure to use the correct serial number for your release of MATLAB. If you are not sure that the serial number is valid or if this is missing, you can request that your serial number be sent to you by contacting Customer Service here: