I got the game by connecting my Xbox Game Pass account via Battlenet. When I start downloading the game, I start downloading it at full internet speed (1000 Mbit). When it reaches 48%, it drops to kbs speeds and does not download the game. I repeated this 4-5 times and the problem is always the same. I have no problems installing other games.
Suggestions:
Pause the update for about 3-5 seconds, then resume. If this fails, then restart all of your internet related hardware (modem/routers, etc) then restart the PC. (Use RESTART not Shut Down)
And make sure you wait till its entirely downloaded before attempting to play, even if the play button is available.
If none of that helps, you may need to visit this thread and look for troubleshooting the battlenet launcher:
-Current list of known fixes and work arounds from the community and other sources!
Don’t waste your time doing any of the things people are going to suggest here as it is on Blizzard’s side and not yours. I have had this problem for months and have found threads going back a year or more. It is deliberately throttled for some reason due to server instability or volume of people or some other metric. Trust me I have fast internet and download and upload daily and this is the only network it happens on and specifically with Diablo 4 for some reason. I have decided to wait for POE2 since thy clearly don’t want us to download this game for some reason.
People will make all kinds of suggestions just ignore them they don’t work many of us have tried changing the download amounts on the settings and rebooted wifi routers and reinstalled the game …etc…etc. Just a waste of time.
Not for everyone though.
I will agree, the game has had issues with downloading files since launch. Won’t deny that. Its the only Blizzard game that has these issues from my experience.
But yes, it can be helped along. The largest thing to make it work better is pausing and un-pausing the download every so often.