See the troubleshooting section at the bottom for addressing game startup errors related to CorsairRGB and INPUT1_3.dll / DirectX
a. Unzip UnrealTournament.zip
b. Place unzipped contents in your desired install location
You have two options here to bypass the Epic Games Launcher (a OR b, don't do both):
a. Install UT4UU (Unofficial Patch) - v10.1.6 *recommended
b. Create a UT4.exe shortcut and add target parameters to it
You must connect to the new master server to enable online play
Follow the instructions here:
If you are working with a fresh windows installation, or haven't previously installed Epic Games Launcher, you may need to install a couple runtime dependencies for UT4 to work.
Error message about missing files related to DirectX when trying to start UT4.
On my fresh Win10 install, the error message complained about missing "XINPUT1_3.dll" when trying to start UT4
Install Microsoft DirectX End-User Runtime - (link here)
Error message related to "CorsairRGB" when trying to start UT4.
Install Visual C++ Redistributable Packages for Visual Studio 2013 - (link here)