For example:
Any ideas?
MacOS High Sierra 10.13.1
Xcode 9.1 9B55
I fixed this by quitting Xcode and deleting all the files in directory ~/Library/Developer/Xcode/DerivedData/.
I had the same issue with Xcode10.1.
All Answers here did not work for me.
I was able to solve this issue only by reinstalling Xcode.
~/Library/Developer/Xcode/DerivedData/ directory and empty trash.