Heres another option which worked for me.
Originally posted by View Post
What I did was go in task manager and make sure that there was no instances of unreal engine running then right click on the Unreal Launcher shortcut properties and add " -SkipBuildPatchPrereq" at the end of the target path. Then it worked fine.
It should look like this “C:\Program Files (x86)\Epic Games\Launcher\Portal\Binaries\Win32\EpicGamesLauncher.exe” -SkipBuildPatchPrereq
Make sure you kill all processes named UE4Editor.exe then try relaunching again.
This worked for me…took a while to load but it’s working NOW!