THis might mean that the preferences are damaged. They are store in a folder in your user folder. If you tell us, which OS you are using, we could tell you the location. After renaming the folder, the contents is rebuld at the next start of Matlab.
Or you have overwritten important toolbox functions. Then restoring Matlab's tool box folders from a backup or re-installing Matlab helps. Do not work with admin privileges to avoid overwriting internal functions.