I have a project that worked fine in beta2 but now it\'s broken with the following runtime error.
dyld: Symbol not found: __TWPVSs26AutoreleasingUnsafePointe
I was getting the same error and I solved it by:
Opening the organizer in XCode 6 Beta3 (Window -> Organizer)
Selecting the "Projects" tab at the top
Selecting my project in the left hand side column
Selecting the "Delete..." button next to the Derived Data location
My swift application now runs on iOS 7.1.2 on my iPhone 4