I've always assumed that you should uncheck "Board is Active" in ACP before doing the following: Backing up the Database Backing up the Xenforo Directory Installing an addon Upgrading an addon But I don't see that as a recommendation in the Help section, so is that really necessary? I guess I would like to understand the processes involved when you do such maintenance, and is there a particular reason why you should turn the board off? For instance, if I have 2 Admins and I shut off the board to install an addon, the other admin can still post (I think). If he does this in the middle of an addon install, can that hose things up? What about on a board with many users online, can an addon be installed or upgraded while the site is live?