"This app contains an app extension with an illegal bundle identifier. App extension bundle identifiers must have a prefix consisting of their containing application's bundle identifier followed by a '.'."
I used to create a widget extension in my project, after a while i deleted it, today I tried to run my app on my iPhone I got this error.
It works well on simulator. And I try to install on other iPhones it also works well. I guess it is a physical device specific problem. I tried delete and reinstall the app and restart my device it did not work, and i checked again there is no extension target or any file in my project, I am still getting the same error.
I had the same problem. Turns out that you just need to clean the project and the build folder with this shortcut command + option + shift + k