Hey Halle, I did as you said
quit Xcode, delete the OpenEars 2.0 download, delete the contents of DerivedData, re-download OpenEars 2.0 from https://www.politepix.com/openears and open up OpenEarsSampleApp.xcodeproj without making any changes to any part of the distribution, and run the sample app.
and Xcode is still reporting “file not found” for all of the OE files. Do you have any further suggestions?