When attempting to build an existing project with Xcode 10 beta 3 I received the following errors:
1) Target 'TestApp' has create directory command with output
2) That command depends on command in Target 'TestApp': script phase “[CP] Copy Pods Resources”
Although not a long term solution, this may get you over the hurdle:
From the File menu:
– Choose Workspace Settings
– From the Build System option, choose Legacy Build System
Rebuild and you should be good to go – until you have time to track down the culprit.