Hi My Gamertag is SWISHY97 and I’m in Australia
I recently reinstalled Halo Wars 2 due to a bug with the game where it needed a 29GB update.
This has already happened to me twice and my friends have been wanting to play the game with me but I don’t know what to do
I would really appreciate any help given
Thanks 
Unfortunately, its a known platform issue. Once you begin downloading a new update, just leave the process alone. It looks like its hung, but most of the time its actually working through its process of finding which files it needs to update. If you interrupt it, it will corrupt the install forcing you to do a complete download of the game. My best advice is start the install, and come back in 20 minutes and see if it has begun making progress. The average time I have seen it start actually showing progress is around 10-15 minutes.
Its annoying, but its not something the HW2 team can fix.