Getting dyld_fatal_error after updating to Xcode 6 beta 4 using swift

Question

I just recently downloaded Xcode 6 beta 4, and my swift project compiles with no errors but before it gets to my code I get a dyld_fatal_error just above start in the call s

Answer 1

Clean and build won't work. You'll need to delete he cache in ~/Library/Caches/com.apple.dt.Xcode* directories. Delete these and rebuild.

Do this every time you upgrade the beta.