Also worked for me on Windows 8 (after not launching the program for a few months). Cheers!
I fixed my problem by sizing display parameters, chosen smallest one for my display. Now no black screen and i work with magnifying glass 
Hey guys I Fixed The Problem also made a video for it at Epic Games Launcher Black Screen (FIXED!) 2019 - YouTube
First Step. Make Sure Epic Games Launcher Is Not Running
Second Step. Go To File Explorer
Third Step. Go To This Pc,
Next Go To Windows (C:)
Next Go To Program Files (x86)
Next Go To Epic Games
Next Go To Launcher
Next Go To Portal
Next Go To Binaries
Next Delete Win32
Next Go To Win62
Next Scroll To You See EpicGamesLauncher
Next Double Click EpicGamesLauncher
Next It’ll Show That You Need To Log In
Next Log In
And Its Done
And If You Deleted Fortnite Press Install
Next It Says Install Location Press Browse
Next Go To Windows (C:)
Next Go To Program Files (x86)
Next Go To Epic Games And Don’t Do Anything Except Press Select Folder
You have to fire in version win 64 no 32
Hey guys how do I correct this on a Mac??
Worked 4 me also Win8.1. Thx
i was had same problem too…try to find the solution on the net for 3 weeks but all came with zero result.
firewall?! Naaaah~
Compatiblility?! Naaah~
DNS?! Naaah~
VPN? Naaah~
launch command?! Naaah~
and when i looked at the properties of the shortcut and see the execution file target it’s like
“C:\Program Files (x86)\Epic Games\Launcher\Portal\Binaries*Win32*\EpicGamesLauncher.exe”
and my thoughs “No dudes, im using 64bit base OS”
then tried to change the target address to :
“C:\Program Files (x86)\Epic Games\Launcher\Portal\Binaries*Win64*\EpicGamesLauncher.exe”
and then…
“■■■■…just like that?! Really?! oh man…my chance to claim it for free was gone just because of that 5 letters”
i think u should try it…it’s work for me tho XD
This worked for me! Thanks friend.