- Quit Xcode
- Finder > Go (hold down the Option key while Go is selected – this will cause Library to pop up)
- Select Library
- Navigate to Developer/Xcode/Derived Data
- Find the folder that has your app name and a jumble of characters behind it, i.e. “MyApp-dfwdfdfakjakjaka”
- Delete the folder.
- Launch Xcode and open your project
- It will be re-indexed and you’ll see a folder pop back into your Derived Data folder for the project.