We can’t update the Unreal Engine Launcher. It’s stuck on 81% and after 30~minutes it’s giving error as “Updating failed”. We have tried multiple times on multiple computers with no success. Tried on Win 7 / Win 8 systems.
When experiencing any issues in the future, please be sure to first run a search at https://answers.unrealengine.com/index.html and then make a post there as well if your issue is not already reported.