I\'m using MATLAB 2015a. few days ago I added a toolbox to my path called SPAMS and for some reason I deleted the toolbox.
SPAMS
When I went to MATLAB set
set
That is because those non-existing path are still saved. Matlab does not list them since the path do not exist. You can simply "Save" the path once after you start Matlab, so update the saved path, and avoid warning in the future sessions.