Xcode 9 - Some folders marked with red text

Question

In my project, there are some folders that have red text. The project compiles and everything works, but I can't understand why only some folders have red text.

Answer 1

Check this.

It means they are not found on disk where your project believes they should be. Control-click and Show In Finder to see the folder location to locate the file and drag it back in to the project, and delete the bad reference.Missing. Maybe you moved them somewhere without deleting them from the project or something.

Edit: Don't delete it before add it first, and you should save backup from the files in another folder, also you have to use source controls like Bitbucket, GitHub, or GitLab.