It can get messy when you turn on automatic signing for an existing project. Automatic signing requires the build settings be set to something neutral, otherwise it thinks you're trying to override the automatic signing. In your case, you got the exactly correct message telling you what to do: go to the build settings for your app target, and choose Mac Developer, which is the first of 3 choices in the Automatic section of the popup menu for the setting. Also do this for any embedded framework targets.Also, if you've added any custom phases to the build that invoke codesign explicitly, delete those build phases.>> The AppName.app: resource fork, Finder information, or similar detritus not allowedIs it possible that at some point you looked at the app bundle's package contents in the Finder? That might have added a .DS_Store file to one of the internal folders. If that's what it is, an Option+Clean Build Folder should solve it.>> I have several MacOS Development certificates … Is there a r