"Check with the developer to make sure Safari works with this version of OS X. You may need to reinstall the application. Be sure to install any available updates for the application and OS X." I'm running a 2013 Mac Mini with Yosemite and Safari 10.1.2. Was working fine until I tried to open it today. I'm also seeing the same message on my Macbook Air, so it must be happening at the Apple account or iCloud level? How do I troubleshoot or fix this?