Unreal Engine 4.18 Shows "Compiling Shaders" Warning and no material is visible

I have mistakenly terminated unreal engine 4.18 process while it was at 45% loading process.
The problem is that since that day, even reinstalling the engine completely, the editor, when running, shows at the righ-low corner, a dialogue window saying “Compiling Shaders” with a Warning exclamation point at left, and thousands of shaders are constantly compiling, while no material is rendered in the project I’m working on.
I’ve tried restarting a new project from scratch and also re-installation as I said before, but I still have the problem.
Maybe the Engine stores wrongly compiled shaders in a system folder?
Please help me, I’m completely stuck.
Thanks in advance for the assistance