I added the Facebook sdk code to my project then I got this error because I already had a json library, so I deleted the Facebook json library from my computer and from the project but I still get this error. I search the whole project for "@interface SBJsonBase" and I only get one result. How can it say it's a duplicate when I only have one interface? Is it including the file twice? Does the search not always find everything?
May be this helps? Delete your derived data and do a clean project, then try to build again