Hi there,Greeting of the day,i was gotting the same issue then i found a solution for this i hope it will work for you as well…just try lunch UE4 on your local drive not on launcher
“C:\Program Files\Epic Games\UE_4.25\Engine\Binaries\Win64\UE4Editor.exe”
Another think when UE4 launches its make Cache on your system…Goto task manager - Details tab - ShaderCompile - Set Priority to High… it will take some time…
i hope its will work for you just try it