iOS - Linker Error, Duplicate Symbol

Check that you have not imported the .m file where it should be the .h file. Doh!

As per your request :

Remove all of your classes from compile sources, then click the + button and search for the term '.m'. Highlight every class, then click add. Build and run again.

I had a similar error when importing third party library with multiple *.a files to my IOS project. In my case removing ‘-all_load’ linker flag solved the problem.