The problem Mr 0.2.1.3.6 Alpha | Launcher 1.0.0.1 (Euro Truck Simulator 2)

Install Available Updates run?

BlackJoni
start climbing out the window with a yellow triangle click OK, nothing is going on.

viktort15
If you have antivirus then disable or MP-launcher (folder) to put in exceptions.

FinistEG
thank you solved the problem.