Update: Bungie said on Twitter that the "Saxophone" issues have been resolved, and it's now looking into the "Chive" error code. We'll keep you posted.
We are actively investigating reports of CHIVE errors when attempting to launch the Destiny 2 PC Beta. https://t.co/kQh3F4RkSPAugust 28, 2017
The Destiny 2 early access PC beta is now underway! Some of you might be experiencing some issues trying to launch the game, however, specifically in the form of the "Saxophone" errors. But take heart: Bungie is aware of the problem, and it's working on it.
Early Access to the PC Beta has begun. We are actively investigating reports of SAXOPHONE errors when attempting to launch the game.August 28, 2017
If you're hit with the error, you'll need to restart Battle.net and then try launching Destiny 2 again, though in our experience you'll simply encounter the same issue.
I have no idea why the error code is called "Saxophone," but according to our number-one Destinymeister Tim Clark, it's a Bungie thing to use "funny" names for error codes: The original Destiny used animal names like Marmoset, Baboon, and Weasel.
Tim, who as you can see below has encountered the error himself, also noted that if you hit "Escape" to dismiss the code as it instructs, it will immediately re-appear. The only way to get out of it at this point is to kill the process via the Task Manager.
In further proof that the PC version of Destiny 2 will be the best, we get fancy new error codes. Welcome, 'Saxophone'. pic.twitter.com/gaCJJN987BAugust 28, 2017
Under the circumstances, this seems appropriate.
Rest assured, once we get the game working Tim, James and Jarred will be running the rule over the technical performance of the PC version.