I am using ARC successfully in my project. However, I have encountered a few files (e.g., in unit tests and mock objects) where the rules of ARC are a little more fragile ri
For Xcode 4.3 the easier way might be: Edit/Refactor/Convert to objective-C ARC, then check off the files you don't want to be converted. I find this way the same as using the compiler flag above.