I don't use a storyboard/xib for launch screen and get this error in Xcode7+.
Starting from iOS9 and Xcode 7 you are required to provide a LaunchScreen.storyboard for your launch screen in order to support the new multitasking feature on iPad.
To opt out of being eligible to participate in Slide Over and Split View, add the
UIRequiresFullScreen key to your Xcode project’s Info.plist file and apply the Boolean value YES.
Find out more on Apple's reference (check last paragraph) or watch session 205 Getting Started with Multitasking on iPad in iOS 9 @ 10:35.