MacBook Pro, Sierra, SD fail to launch

[ArizonaDAK]

I have been using SD for more than a decade. I finally bought a new MacBook Pro this week. It came installed with Sierra 10.12.5. My SD is version 2.9.1. The problem is, SD won't launch. I get the spinning wheel of death. The icon appears in the dock, but it never materializes beyond that. I have to force quit to make the icon disappear. What is going on and how do I launch SD?

[dnanian]

Have you tried restarting your Mac and peripherals? If so, re-download and install a fresh copy by running it from the download image.