Xcode fails without specifying and errors

Question

All of a sudden my project fails to build in Xcode. If I look at the log I see all the needed dependencies being built, and then I get a strange error:

Verify fi         


        

Answer 1

Happy 2019, everyone, but sad to say this can still happen in Xcode 10.2.

I had four projects open in Xcode but only one failed in this way. I tried a main menu > Product > Clean Build Folder. The little progress spinner started up and 5 minutes later was still spinning. Hmmmm.

So I quit Xcode and in Terminal did a cd ~/Library/Developer/Xcode/DerivedData. Although ls -alww showed only one subfolder named after each of my other projects, as expected, there were five subfolders whose name began with the name of the problem project. I deleted all of them

rm -R ProblemProjectName-*

and relaunched Xcode. Problem solved.