Apple decided to sneak in a couple more requirements alongside notarization that we’ll just have to deal with. That’s right, notarizing your app takes 4 steps, of which just one is actually, well, notarizing the app.
“Appname.dmg” can’t be opened because Apple cannot check it for malicious software. If you try to launch an unnotarized app that should be notarized on MacOS 10.14.5, you’re greeted with the following ominous sounding error message: When I first encountered the issues, the error message couldn’t even be found on Google! Unfortunately there is not a lot of information out there.
MacOS 10.14.5 came out a couple of days after I launched my (then unnotarized) application Polypane, leading to a number of complaints from users not able to install the app. This is how to successfully notarize your Electron application.
That means that aside from signing your application, you will need to notarize it as well. Starting with MacOS 10.14.5, all signed applications by ‘new’ developers will need to be notarized or they will trigger Apple’s Gatekeeper software and prevent users from installing your app.