I am running Xcode 9.2 on 10.13.3 and just today ran into a problem with Xcode not recognizing Main.storyboard on an app that I am building. It worked on Friday and then today when I opened the app to work on it I get the following error:
.../Base.lproj/Main.storyboard: Interface Builder could not open the document Main.storyboard" because it does not exist.
Visually the file is there but does not respond. It is listed correctly in info.plist.
I tried pulling versions from Time Machine from last week and I still get the same error.
Is there anything short of rebuilding the storyboard that I can do to get Xcode to recognize it?