Signed application cannot be opened once downloaded - ("unidentified developer") error I have developed an application for OS X. As changes to this application are pushed to my code repository, a build server (Jenkins) automatically detects those changes and kicks off a build process. As part of that build process, I sign the generated binaries with a certificate I have received from Apple. Once that process completes, I am able to verify that the application has been properly signed by running:

$ codesign -v ./MyApp.app


Here is the strange part: If I download those binaries directly from Jenkins and copy them over to a Mac, I can run them without issue. However, if I host those binaries on a web server and download them via HTTPS, I receive the "can't be opened because it is from an unidentified developer" error and am unable to proceed.

Can anyone shed some light on what might be happening here?
When you downloaded apps with Safari an extended property is set on the file to mark is as quarantined. Another extended property is set to save the URL you've downloaded the file from.

Depending on your security settings you will be prompted the first time trying to start the downloaded application. You will be informed that you have downloaded the program, the URL and - depending on your settings - be allowed to bypass the prompt and run the program.

You can remove the attribute manually to allow you to script these downloads. Run the following command in Terminal.app:

xattr -d com.apple.quarantine path/to/file/filename