Hey! Randomly out of nowhere my client has started crashing as soon as I open a widget blueprint. Nothing I can do seems to fix it. New projects and known previously working other projects now won’t open widget blue prints 
Help!
Managed to replicate this, figured out what it was causing the crash.
I had closed the Animation windows. Soon as I had saved, closed and then tried to open another? It crashes.
Reset layout to default restored things to normal.
Guess I’ll leave Animation there for time being! Hehe
Hello ,
This is a known issue (UE-23217) that has been submitted to the developers for further consideration. I have provided a link below to the original issue. Please feel free to follow that thread for future updates.
Link: Assertion failed: IsValid() File:D:\BuildFarm - UI - Epic Developer Community Forums
Make it a great day