issue after xcode update PCH file built from different branch [duplicate]

Question

I just updated to xcode 4.6.2 and upon running the program I am getting the following error:

 PCH file built from a different branch ((clang-425.0.27)) than the compiler ((clang-425.0.28))

How do I fix this error and where is it coming from. It has come up from no where I have never seen an error as such before.

Thanks for your help in advance :)

Answer 1

The answer was simple... I simply had to clean my program as suggested from the comments above