I had the same issue others had with this update and reinstalling the entire game as opposed to the “small update” another forum user pointed this out and I believe he’s correct: if you have H5 installed on an external hardrive and if you have done a factory reset recently (I’m thinking Bf1 trial popup that made a lot of people factory reset) then your system settings automatically reverted back to installing all new content on the internal hardware . Thus , the “small update” installed on the internal while H5 is stored on the external causing some issues . To fix this , go to settings >storage and select your external as your default location.
At least I think is what happened and it should help with future updates.
I don’t have an external hard drive. I wish 343 would respond to this. I can’t play all month…
Nope don’t have an external hard drive and I haven’t recently reset anything.
91.37gb update regardless. 
i cant install halo 5 period
The lack of response is this is pretty sad considering we are 2 days out from the 15th Anniversary.
Thanks Renegade! although I did not factory reset my console I do have an external hd that this game was stored on.
I can shed some light onto how random this mess is, we have 2 consoles, both went to update at same time, my console, 220mb update, no issues, other console, over 90gb. there was no update difference and had recently played both, with a 200gb cap I can’t update the second console. this is rediculous and will kill he game, already noticed massive drop in players online. if 343 doesn’t address this soon, then they won’t sell another game to me or about 20 of my mates.