iOS "The sandbox is not in sync with the Podfile.lock"解决方案

更新Cocoapod之后出现问题：

diff: /../Podfile.lock: No such file or directory
diff: Manifest.lock: No such file or directory 
error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.`

解决方案：

关闭现在的工作空间，删掉以前的xcworkspace，然后重新pod install，install完后，重新打开项目，clean＋build项目，运行

rm -rf MyProject.xcworkspace
pod install

方案提供：

http://stackoverflow.com/a/19131855/3458781