编译错误“The run destination My Mac 64-bit is not valid for Running the scheme '***'，解决办法

1. iOS APP Project or Mac APP Project编译错误提示：
“The run destination My Mac 64-bit is not valid for Running the scheme '***'.
The scheme '***' contains no buildables that can be built for the SDKs supported by the run destination My Mac 64-bit. Make sure your targets all specify SDKs that are supported by this version of Xcode.“

2. 问题原因：
工程设定的SDK Version和PC上安装的Xcode对应的Mac or iOS SDK Version不一致。

3. 解决办法：
Solution，to change the Base SDK Version:
1) Click on the project icon in the left hand panel.
2) In the right hand panel that appears, select Build Settings » all.
3) You'll see the option to change the "Base SDK". Architectures » Base SDK.
4) change Base SDK option to your project corresponding SDK version, OS X SDKs or iOS SDKs. eg: OS X 10.8 or iOS 6.0.