They always warn you to take precautions when you install betas, but foolhardy (and lazy) girl that I am, I rarely do.
Moving from the third Flock 2 beta to the official release, I lost my entire Accounts & Services sidebar. There was nothing to click, but I clicked anyway – hoping a link or a button would appear, like Jack Skellington in Christmas town.
I removed the Flock folder under Library/Application Support, imported my old Safari data to give Flock something to do, and logged in to my social networking and media sites via the myworld page (which I always ignored before, but which is turning out to be not a bad thing). At last, everything works.
Faith in Flock restored, I can now go to sleep.