Cura2 vs 6.2.21 - Mac OS X (Sierra and El Capitan) - When launching application, user is prompted to confirm that they want to open an application that was downloaded from the web. User selects "open" and dialogue goes away but application also never opens and disappears from the application tray at the bottom of the screen. Once you double click icon a second time, application opens.
More investigation indicates that this is a problem with with how MacOS quarantines files that have not been signed. We might only be able to resolve this by digitally signing the package with a developer key. This could potentially be an ICS developer key so that ICS does not need to agree to the Apple developer agreement. We'll need to discuss if this is a viable option.
We spent significant time investigating this and trying signed binaries and were not able to suppress the install warning. According to our Mac expert, signing a binary will still generate a warning about it coming from the Internet and the user needs to confirm to run it. This is causing it to only launch the second time. There is no way around the warning unless the app is released to the Apple store. It will only happen the first time you run a given version.
Signing is still desirable to make it clear the app is coming from a real developer but won't avoid this warning dialog. The recommendation is to continue to document that the user needs to adjust their security settings: https://www.lulzbot.com/learn/tutorials/cura-lulzbot-edition-installation-osx
And somewhere we should mention the known issue that it will not run the first time you initially open it after downloading.