Long installation time on Xbox One

Your internet speed is likely at fault here.

I have just installed the game, and here are my observations:

• It took about 30-45 minutes to install enough of the game to run, on an Xbox Elite console. Regular consoles may take a little longer, as the elites solid state drive performs faster, allowing quicker install and loading times.
• As of 1/4/2016, Battlefront requires approximately 8.5 GB of updates. This accounts for patches, as well as new content; There is at least one map (The Battle for Jaku) that was released as a free DLC, that was not immediately available with release. This took about an hour, for me. However, I have a fast cable internet connection, for where I live.
• The reported percentage on the Xbox Dashboard appears to be the percentage of game installed directly from the disc. When the Xbox reported "42% complete", Battlefront reported "12% complete".
• Both progress bars are in no way designed to progress smoothly. I had several pauses, before the bar would jump anywhere from 5% to 30% ahead of itself. I speculate that the bar represents chunks of varying sizes, so 5 updates would individually account for 20%, even if one update was considerably larger (and took a far greater time) than the other.
• At approximately 42% installed, you can actually play Battlefront. However, until you have completed the install, you are limited to a game of Darth Vader vs The Rebels. At this point, however, you can confirm that the game actually runs. Furthermore, as I said before, your given a more accurate progress bar in game.

What if I have extremely slow internet, and wish to forgo the update?

At this point you want to be considering the capabilities of your internet. If you are experiencing considerably slow install times, as a result of internet speed, it is worth asking if you can normally get away with the speeds required to play a game online.

While many games will still force you to update, and disconnecting from the internet can forgo these extra loading period, Battlefront is predominantly an online game.

Star Wars Battlefront only took me 5 hours to download on PS4 but my friends with an Xbox One had to wait a whole day for it to download so just leave it running for a day and you can come back to it and play