If you believe the avalanche of Xbox One rumours that have come to light over the last few days, the Xbox One's first big update is due in March. We've had a few teeny tiny updates since launch, of course, but this one's rumoured to be a real lunker, making radical changes to the console's social features.
In preparation for this wondrous and possibly fictitious event, but also in anticipation of all your Xbox One update-related problems, here are a few worst-case scenarios you might run into when trying to install and run updates on your console, to make any fixes run as smoothly as possible.
According to Xbox Support, whenever your Xbox One displays the green start-up animation (like when it restarts after an update, for example), it's running a full system check on all its hardware components, validating all firmware and the operating system. "This is very similar to the way a PC starts," Support says, and "this start-up animation screen can take several minutes before transitioning to the next screen because of this full system check."
Basically, be patient - you could be looking at this screen for quite some time, but unless it takes longer than ten minutes to get going, there's nothing sinister afoot. The Xbox One is pretty much designed to be forever on stand-by, so when it's booting up from scratch, it'll need a few moments to gather its thoughts.
If the green animation hangs around for longer than ten minutes or so, however, it has outstayed its welcome and needs to be given a swift boot up the backside. If a second or even a third try yields the same stalled results, you'll need to run the Offline System Update Diagnostic Tool, and you can find a step-by step guide of how to do that here. Note that before you begin, you'll need a USB drive formatted as NTFS with a minimum 2GB of space, and a PC with both an internet connection and a USB port nearby.
If you can't complete the Offline System Update Diagnostic Tool (man, that's a mouthful), you may have a FUBARed console on your hands. Get to the Xbox Online Service Centre, stat.
Now then, let's say your console can power down and restart just fine, and it's the installation of the update itself that's the problem. Before, during or even after a system update has started, you might receive a message saying there was a problem with the update. The problem is likely to stem from either a network or caching issue, but if you hold down both triggers and both bumpers whilst the console is displaying this screen, you'll get a new screen displaying an update error code. More on these in a moment.
First off, cover the basics and double-check your console has a working internet connection. You can do this via the error screen itself. If you're working off a wireless network, you may want to plug your Ethernet cable into the console for the duration of the update. If everything appears all good and you get an error screen again after a second attempt, Xbox Support suggests you try the old power cycle of turning everything off and on again, as this will reset the network card and clear the cache. If that also fails, you're going to have to try the good old Offline System Update Diagnostic Tool (let's just call it the OSUDT from here on out, shall we?) again.