Blueprints disappearing

Yesterday I started following the endless runner tutorials on Youtube, I had to leave while I was making the item. I came back today and found that most of the code I’d done had been deleted, I know that I saved because the blueprints themselves(The ones in the attached picture) were still there. Does anyone know the cause or a fix for this?

-are you 100% sure that you have saved your blueprint?
-what exactly is missing?
-have you already checked your functions? :slight_smile:
-which engine version do you use?