打开terminal，输入如下命令：
find ~/Library/Application\ Support/Developer/Shared/Xcode/Plug-ins -name Info.plist -maxdepth 3 | xargs -I{} defaults write {} DVTPlugInCompatibilityUUIDs -array-add `defaults read /Applications/Xcode.app/Contents/Info.plist DVTPlugInCompatibilityUUID`
具体原理，详看下面链接
http://joeshang.github.io/2015/04/10/fix-xcode-upgrade-plugin-invalid/
原文：http://www.cnblogs.com/feiling/p/4915552.html