Microsoft has warned that the Xbox One's day one system update will need around 15-20 minutes to download.
The mandatory update will change the system's firmware to reflect the console's post-policy change state - specifically, Xbox One's need to be online at least once every 24 hours.
Speaking to IGN, Microsoft's Marc Whitten gave no explanation for the update's extended download time (expected busy servers? Large file size?) but promised the company was working to make the process as painless as possible.
"We are optimising Xbox One so that the day one update is as fast as possible," Whitten said. "While we're still finalising the details, we expect that the download will take between 15 and 20 minutes for most users."
Whitten also confirmed that all Xbox One games would be able to take advantage of dedicated servers through the cloud and reiterated the fact that the Xbox One's dashboard will continue to be tweaked post-launch through further system updates.
Microsoft changed its mind on a number of Xbox One policies over the summer - notably, its need to connect to the internet every 24 hours, its digital game policies and sharing options, and the fact the console and games will now be region-free.
But these changes came too late to be fully supported in the launch version of the console - hence the need for a day one patch.