Several users reported the same problem after the recent update (for example: Control panel in Garage Band is empty aft… - Apple Community). I have not yet seen any solution.
I can make the Smart Controls vanish, when I resize the GarageBand window and drag the dividing line between the Track area and the Smart Controls. Then the Smart Controls panel vanishes completely. Try to make the Window as large as possible. Then toggle between the Smart controls and the Editor. Will that bring the full controls back?
Perhaps GarageBand cannot write to the preferences files in your home folder. I would try to repair the permissions on your home folder as described here: Resolve issues caused by changing the permissions of items in your home folder - Apple Support
If that does not help, I would remove the GarageBand preferences files. It frequently helps, if items in the graphical user interface are missing.
- For GarageBand '11 the preferences are stored in ~/Library/Preferences/com.apple.garageband.plist/
- For GarageBand 10 you need also to remove the Container:~/Library/Containers/com.apple.garageband10/
You user library may still be hidden, as is the default: To make it visible in newer systems:
- Quit GarageBand .
- Select the "Home" folder icon (the little house) in the Finder's sidebar and press the key combination ⌘J to open the "view options". Enable "Show Library Folder".
https://discussions.apple.com/servlet/JiveServlet/downloadImage/2-33265182-970555/Screen+Shot+2013-12-29+at+19.42.20MEZ.PNG
- Then open the Home folder and open the Library folder inside and navigate to Preferences.
- and drag /com.apple.garageband.plist/ to the desktop.
- Then navigate to Containers and drag
- ~/Library/Containers/com.apple.garageband10/ to the desktop.
- Restart the Mac and try again.
This is described in more detail here: HangTime's fix for oddball problems:
http://www.bulletsandbones.com/GB/Tutorials/DeletingPreferencesFiles.html
