Xcode gives me this message every-time I try running my app on my iPhone. (Works fine on the simulator.) (And this occurs in every project I have.) (I also just downloaded Xcode again.)
This is the message I get.
App Installation Failed.
Unknown Error Occurred.
How do I fix this error?
Alright, it was a simple fix:
Go into Xcode Preferences -> Accounts -> More Info. Hit the refresh icon.
Clean your project. Project -> Clean.
Force quit Xcode.
Reboot Mac and Device.