I filed a bug report: FB17507612 There are mechanism in the system to prevent apps from masquerading as "each" other [...] Thanks for the explanation! Try adding the "com.apple.security.network.client" capability. My initial read (so I may have missed something) of our code is that this is what NetAuth is looking for and it's the easiest thing to test. This did not resolve the issue. I enabled every capability I could find and even tried com.apple.security.temporary-exception.files.absolute-path.read-write without success. If #1 doesn't work, then try disabling the App Sandbox and see if that resolves the issue. This is will quickly determine whether the issue is specifically a sandbox issue (if it works) or not (if it fails), which is important to a more in depth investigation. This did resolve the issue after changing the bundle identifier. Try setting "NULL" for the mount point (use the system mount path) and dropping kNAUIOptionNoUI. Again, both of these are to try and clarify what the system's actual issue is, not to force you to use that particular configuration. This did not resolve the issue. It looks like the way you would mount the share using the Finder but it does not work. In all cases, the mount point is briefly created—appearing in Finder as a folder named after the share—but it disappears almost immediately, as if the folder were created and then deleted right away. Kind regards, Simon