I was able to move forward in 4.7.1 - my packaging turned out me referencing my UMG widgets from deep within my actor - by brokering my calls through functions instead of getting an instance to my controller and going into my widgets and calling methods from my actors - also did cause my editor to crash when loading at 93%
if your editor crashes on project load it should tell you in the what crashed it - its probably a suspect uasset, if you remove it, or things calling it - your project will eventually load, you can re-add your widget and relink the nodes (its a pain but the only way I could move forward)