編譯錯誤“The run destination My Mac 64-bit is not valid for Running the scheme '***'，解決辦法

1. iOS APP Project or  Mac APP Project編譯錯誤提示：
“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.  問題原因：
工程設定的SDK Version和PC上安裝的Xcode對應的Mac or iOS SDK Version不一致。

3. 解決辦法：
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.