Q: Garageband starts on wrong display

Hey Mike,

I see that GarageBand is always opening on a secondary display, even when that display is off.  To get started with troubleshooting this issue, I'd like you to enable the option "Close windows when quitting an app" in your System Preferences.  This check box is found in System Preferences > General.

                 

Close windows when quitting an app

Select to close app windows when you quit an app. The windows won’t reopen automatically the next time you open the app.

General preferences

Take care.

Hey OneFisheye,

Since it's still opening on that secondary display with that option enabled, then it appears that GarageBand has been assigned that space in Mission control.  I suggest that with GarageBand open, you then open Mission Control, and drag the GarageBand application window to your main space.

Open Mission Control

Use any of these methods to open Mission Control:

• Swipe up with three or four fingers on your Multi-Touch trackpad or Magic Trackpad.
• Double-tap the surface of your Magic Mouse with two fingers.
• Click Mission Control  in the Dock or Launchpad.
• Press the Mission Control  key on your Apple keyboard, or press Control–Up Arrow.
• In OS X El Capitan, drag a window to the top of the screen.

 

Move a window to a space

• Move a window to a desktop space: Drag the window to that space in the Spaces bar. 
• Move a window to a full-screen space (Split View): If an app supports Split View, you can drag its window to a full-screen space in the Spaces bar. The combined space shows the names of both apps. Click the space to see both apps in Split View.

If your windows are grouped by application, an app icon appears at the bottom of each group of application windows. Drag the icon to move all of the app's windows at the same time. To turn on this feature in OS X El Capitan, choose Apple menu > System Preferences, click Mission Control, then select “Group windows by application.”

Use Mission Control on your Mac

Take care.