Can't connect without crash / Installing UE4 offline

Hello, I can’t connect without crash ("… has stopped working") on multiples computers.
Tryed it again and again, searched every solutions, nothing that works.
Can you help me?

Or

If you can help me to install UE4 in offline mode ( I’ve got already an installed version on my personal PC)

Hi Thenoimio,

I’m sorry that you are having an issue with the Epic Games Launcher. In order for us to offer the best support, we have recently modified the process for how Epic Games can help troubleshoot your Launcher issue. Please visit http://help.epicgames.com/ for technical support, here you can find information and solutions for common issues, as well as a contact form if you still need additional assistance. Thanks!