I actually have no idea what is happening, I started using unreal 4.15 for the first time, got a map going, and decided to add the addon “Polypixel freebie pack” to the project.(The freebie pack even states that it supports the latest version) All I can say is simply clicking “Add to project” and then selecting my latest project crashes the Epic Games Launcher.
Hey moosyman,
For Launcher issues, please head over to http://help.epicgames.com/
On the site, you’ll find multiple articles that pertain to various Launcher issues and fixes, as well as an Email Us button on the side of the page that you can use to get in touch with one of our support staff for further assistance.
Have a great day