Xcode 7 - Code coverage data generation failed

Question

When I run my tests I get an error:

Code coverage data generation failed.
Unable to retrieve the profile data files from \'UIDevice\'.

Answer 1

I experienced exactly the same error and eventually got it working, these are the steps I took.

1. Tried restarting Xcode and the simulator, after cleaning and deleting the app, that never worked.

2. Then I restarted the Mac as suggested, but that still didn't work.

3. Then I chose a new device to test against in the simulator, was previously using 5s and switched to 6, and that worked.

Interestingly, when I switched to the iPhone 6 simulator, it showed the Apple logo with a loading bar, before running the app and working.

When switching back to the 5s simulator it did exactly the same, with the Apple loading bar, which it hadn't done before, and then the 5s worked.

So it looks to be a simulator issue, and switching to a different device worked. Resetting the content and settings may be the solution for a non-working device.