Just signed up to chime in: I had the same problem as in the video, and Kman's delete of the MC (not Forge) folder also worked. I had installed a modpack (JANKY Skyblock) via the Twitch system using the Native Launcher that was using MC 1.14.4 and Forge 28.1.96. The FML Early Progress window was showing up, scanning all the Mods from the pack, but then about 9 seconds later, I'd be at the vanilla screen with no mods loaded. Deleting the Twitch profile and recreating did not help. Deleting the Forge folders in the \Install did not help. But, deleting the MC folder was the trick. (Including all these details to hopefully SEO this thread so other folks don't have the same hour+ search I did for a solution) Sorry y'all here have to deal with trying to help folks with weird launcher problems.