Why, after downloading updates does "finishing things up" take so long?

The speed of your internet has nothing to do with the finishing things up step, that happens entirely on your system. Any access of the net would be very small data exchanges

In addition, your internet speed doesn't affect the speed you get from Xbox servers

finishing things up means that it is decompressing and patching the files. If you're on an Xbox one, the hard drive is much slower than the one in series, and therefore it takes a longer amount of time

Thank you for the reply, but I'm on series x and don't understand why things takes so long, frustrating as I have 500mpbs wired broadband

I'm also on a Series X and I've noticed this too. With fairly small games, sometimes I can delete the entire game and re-download it faster than I can download a small update for it and wait for the "finishing things up" thing to finish.

If it's decompressing and/or verifying data, I don't see why it would sometimes take way longer to do that with a small update for a small game, compared to a huge update for a huge game, but it does. Unfortunately I've never seen an MS dev give a full explanation of what exactly is going on during the "Finishing things up" stage, likely because they're under NDA.

The discs have to be installed because the disc readers can not read them fast enough during gameplay. All discs have to be installed, there is no way around that (PS4 does the same thing). When you are installing, it will usually download updates for the
game at the same time. If you try installing while in offline mode, that can cut down on the time.

Thanks I'll try that. I'm still not happy with this installing games though and waiting ages and only being able to have several games installed at once. It's a backwards step in gaming in my eyes.