Failed to download ‘http://cdn.unrealengine.com/dependencies/UnrealEngine-4433328-772358af280a4a978d29c80fcb38b829/08eaff52c70678bc6abb941ee70dd7aebd936c91’: Can’t read from pack stream (CorruptPackFileException)
Create an exception for the unreal engine in your anti virus software + firewall and try again.
I had a similar problem with avast / unity engine