OS X Mavericks: If you changed your display’s resolution and now there’s no picture
You may have selected an unsupported screen resolution, causing the screen to go black temporarily. The display may reset its resolution automatically, or you may need to take some simple steps to correct it.
Reset the resolution automatically
- Wait 15 seconds to see if the Mac resets the display resolution on its own.
- If that doesn’t work, press the Esc (Escape) key, which should revert your display to the previously selected resolution.
- If your display is still black, restart the Mac by pressing Control-Command (⌘)-Eject.
Restart your Mac in safe mode and choose a new resolution
If you couldn’t reset your display’s resolution automatically, restart your Mac in safe mode and choose another resolution.
- Shut down your Mac by holding down the power button.
- Restart your Mac, and immediately after you hear the startup tone, hold down the Shift key. (Don’t press the Shift key before you hear the startup tone.) Release the Shift key when you see the progress indicator below the gray Apple icon.
Startup may take a bit longer than usual, but your display should begin working correctly.
- Choose Apple menu > System Preferences, click Displays, then click Display.
- Select a resolution that is supported by the display.
- Restart your Mac.