title: pbxcp issue, file not found but it's definitely there
body: <p>So I've been working on different images for my app, seeing how it looks, replacing it...all has been well until earlier I replaced a file (checkmark.png) with an updated version I made, now when I build I get <code>pbxcp: checkmark.png: no such file or directory</code>. I have removed the file and re-added multiple times, I've renamed the file and replaced every instance of the file in my code with the updated name. No matter what I can't get rid of this error, all the googling I do ends up with a lot of unanswered posts, some people saying to "Clean" the project, I've tried everything I can and can't get rid of this error. Anyone have any ideas?</p>