After an update of OSX it’s best to trash the prefs file so that they get automatically re-built on next launch.
Quit Lightroom
Launch Finder and find the user Library by clicking the Go menu whilst holding down the Optn (alt) key (n.b. the library is hidden until you press the optn key) and inside the Library folder select the preferences folder. Then trash the following file:
com.adobe.Lightroom5.plist
Quit Finder and re-launch LR5