I tried launching 4.8 this morning and the splash screen just stopped with the message “Initializing… 45%”, left it running for about half an hour with no change. I know this isn’t the same issue as Can't launch UE 4.8,Can't launch Unreal Engine 4.8 - Installation & Setup - Unreal Engine Forums since I’ve run 4.7.6 in the past. Anything else I can try?
It’s possible that there is more to this bug than we realize. Could you try downloading and launcher 4.7.6, then try reopening 4.8? Make sure to leave 4.7.6 on your machine while you do it.
I had actually tried that before posting my question. I ended up just letting it sit for ~45 minutes while I did other things and it did eventually finish launching. My laptop is somewhat low-end but I’d never had it take that long on any of the previous engine versions. It looks like that was a one-time thing though, it starts up much faster now that I’ve successfully launched it once.
I don’t even get the splash screen. 4.7 took out my video and caused serious issues that were unrepairable with windows 7 64. I had to reinstall. Now 4.8 won’t even load. Which is a serious issue because I will not go back to 4.7 because it destroyed my system twice.
It’s not the same problem, but for anyone getting the splash screen stuck at 72% and losing internet connection, with a Bigfoot Network Killer network card: I recommend doing what is mentioned in this link: Why does the 2nd player have a black screen with two clients enabled? - Multiplayer & Networking - Unreal Engine Forums
That solved it for me.