The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.

出现这样的错误：

error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.

具体如图：

我按照提示在终端打开工程，pod install 和 pod update 都试了一遍，然并卵。只好拿出杀手锏：

Project -> Info -> Configurations -> Debug 改为 Pods.debug, Release 改为 Pods.release， 如图所示：

 搞定啦！