App crashes in Release build but not in debug

Question

As I said in the title, I am writing an app for iPhone which runs perfectly in debug mode but when I build it as release and install it via TestFlight, it crashes. Due to t

Answer 1

Apple also describes a known issue. I describe it briefly in case someone is look for answer and the previous solution doesn't work.

Check your crashlog for errors like

Dyld Error Message:
  Library not loaded: @rpath/libswiftCore.dylib

or

[....] [deny-mmap] mapped file has no team identifier and is not a platform binary:
/private/var/mobile/Containers/Bundle/Application/5D8FB2F7-1083-4564-94B2-0CB7DC75C9D1/YourAppNameHere.app/Frameworks/libswiftCore.dylib

and follow apple guidance if you have similar crash output like the one above.

PS: You could check the log easily even under Window ->Device in XCode. click to the device and click view device logs.