SwitchResX - FAQ - it broke everything https://gist.github.com/ejdyksen/8302862 external mac monitor blackscreen - default resolutions on retina wrong sudo rm -Rf /private/var/db/.com.apple.iokit.graphics sudo rm -Rf ~/Library/Preferences/ByHost/com.apple.windowserver.plist sudo rm /Library/Preferences/com.apple.windowserver.plist rm /Library/Preferences/com.apple.windowserver.plist rm ~/Library/Preferences/com.apple.windowserver.plist cd /System/Library/Displays/Contents/Resources/Overrides/ sudo defaults delete /Library/Preferences/com.apple.windowserver.plist DisplayResolutionEnabled /System/Library/Displays/Contents/Resources/Overrides /Library/ColorSync/Profiles/ ~/Library/ColorSync/Profiles/