With "Application is background only" in the .plist of your app, it is possible to specify that an app is background only. Apple calls this an "agent". This can be combined with an icon on the right side in the statusbar (apple bar/menubar) via nsstatusitem. I want to make an app that runs continuously in the background. When the user starts (via a menu on the statusitem) the GUI app, it should look and act like a regular app with dock icon and menubar. The background app should also continue running at the same time. This is probably possible by just making two different apps. It is not a document-based app, but it is a core-data app. So the data and the datafile is (should? will? can't?) identical for both apps. What would be the best approach to tackle this? Two separate apps (but how would you deal with the datafile issue) or 1 app where the .plist is changed on the fly (or is that not possible?). As always, thank you for your time and answer!