Short error:
file was built for archive which is not the architecture being linked (i386)
Expanded:
For some simulators, I receive these e
I solved it by deleting the DerivedData
directory.
Steps:
In Xcode, go to Menu bar → Window → Projects.
In the Projects window, choose the project on the left.
Click the Delete... button for Derived Data. When asked to confirm, click Delete.
Rebuild the project.
For Xcode 8, see this Q & A:
How to delete derived data in Xcode 8?