I downloaded 4.18 unreal engine today and every time I try to launch it, it reaches 45% and then just stops loading completely. I’ve tried clearing storage and that doesn’t seem to be the problem.
Impatiance is the Problem 
its not stuck at 45% its compiling your shaders. Depending on your Project size and Hardware it can take a while. You can open your Task Manager and you will see that the shader Compilers currently doing their work there. Get a Coffee watch some YT Videos let it run. Next time you open your Project it will not recompile the shaders and load up faster.
Thanks, I looked at how the CPU was running and it turns out, I had 5 unreal engines all trying to load at the same time. Thanks! Coffee is too strong for me doe