I had a similar error when I updated to xcode 9.2 and macOS 10.13.2, and I solved it by downgrading my cocoapods from 1.3.1 to 1.2.1.
We are also facing same problem here. We have a huge project with around 3900 files in Build Phases > Compile sources.
Whenever we faces this Zombie error, we used to shorten the file paths and project is maintained at the root directory in order to shorten file path and it was working. But its all temporary solution. Now we reached to a level where nothing else works and we need to have permanent solution to the same.
Possible reason is, maximum limit on number files by Xcode. Only then this probelm can occur.
And I'm not using any cocoapods in our Project as well.
Any solution please suggest.
XCode version : 9.4.1
MAC OS Version : 10.13.6
Verify final result code for completed build operation
Build operation failed without specifying any errors. Individual build tasks may have failed for unknown reasons.
One possible cause is if there are too many (possibly zombie) processes; in this case, rebooting may fix the problem.
Some individual build task failures (up to 12) may be listed below.