Been banging my head agains the wall for awhile now. My Xcode project went a little haywire while refactoring, and refused to build. I've squashed all the other errors, except one last linktime error:
Framework not found AudioUnit
I have the AudioUnit headers, the AudioUnit.framework is included in my project as it was before (Targets > Get Info > General > Linked Libraries > + ), but I cannot figure out why it does not work now. AudioToolbox.framework is also included.
Remove AudioUnit.framework and add CoreAudio.framework
Helped for me: removing AudioUnit.framework, then adding AudioToolbox.framework, Clean, Build
In my case compiler lies about AudioUnit, in fact for project was required only AudioToolbox.framework.
I had already tried swapping out all available audio frameworks (AudioToolbox, CoreAudio and AudioUnit) and no configuration worked. Something funky with Xcode was going on.
I reinstalled Xcode and migrated the code to a new project. Now it builds fine with the exact same frameworks as I had before. A frustrating solution, but a working one nonetheless.
来源：https://stackoverflow.com/questions/1756212/framework-not-found-audiounit