For the longest time, I couldn’t install Diablo 1. I was getting the:
Whoops! Looks like something broke. Give it another shot.
Error Code: BLZBNTAGT00001389
Nothing worked, no matter how many times I restarted battle.net and my computer. Or tried to reinstall or update.
Today I decided to change the install location from D drive (which is an external hard drive plugged into a USB slot) to my E Drive (which is an SSD drive using the internal expansion slot) Now it runs. I was having the same issue with Microsoft Flight Simulator not running on the external drive and thats why I got the internal SSD drive in the 1st place.
Every Diablo 2,3,4 Starcraft 2, Heroes of the Storm, and Hearthstone all work fine on the external drive, Diablo 1 is the only exception of the games I have on Battle.net. I’ve had a couple other games that ran into issues like Balder Gate 3 and I forget which others.
As this is a laptop, expansions is limited, I’ve devoted the C drive solely to Windows as its not big enough for games so i didn’t even bother trying that out