In some circumstances, changes to your Windows-based computer can cause the MATLAB icon to change from its traditional L-shaped membrane (the MathWorks logo) to a generic sheet of paper.
To restore the MATLAB icon, you should right-click on any impacted MATLAB icons, select 'Properties' and click on the 'Change Icon...' button. From here, click 'Browse' and navigate to the matlab.ico file that is located in your $MATLAB/bin/<arch> folder, where $MATLAB is your installation directory. You will then need to click Apply.
By default, the full path to the matlab.ico file is:
For Professional -
C:/Program Files/MATLAB/{release}/bin/win64/matlab.ico
For Students -
C:/Program Files (x86)/MATLAB/{release}/bin/win32/matlab.ico
Note: In these paths, the {release} information will need to be replaced by your actual release number (i.e. R2012b, R2013a, etc.), and the win32 or win64 folder may need to be adjusted based on your computer's architecture.
If this matlab.ico file is missing, or selecting it doesn't resolve the issue, you may want to reinstall MATLAB to resolve the issue.
