The forum was down between some time last night (after ~1100Z) and about an hour ago because it wiped out its settings file. I'm still not sure why it was writing to it then, but it made the forum think it wasn't installed and try to redirect everybody to the setup page.

I have it up and running again with all posts and users present, but some other aspects may not be as expected. I may not have enabled the same extensions as before and it's possible some of the ones that are aren't working correctly. I had to back up the database and reinstall, then re-enable extensions and restore the database backup. In particular, the Notify extension may not be working (I had to create its database tables manually, since it didn't do it itself on reinstall).

If you notice things that aren't as they should be, let me know.