Paths for Maya's Prefs:

 

renaming the "prefs" folder to something like "prefsOld" found in the following location:

/Users/[yourusername]/Library/Preferences/Autodesk/maya/2013-x64/

----------

The Library folder is a hidden folder so you will either need to change the setting to show hidden folders or from the main desktop go to Go > Go to Folder and type the above directory. Once you have renamed the "prefs" folder to "prefsOld" restart Maya and when prompted to select the option to Create Default Preferences. A new prefs folder should be created. Test and see if the issue is resolved.