Just update fromt 5.2 to 5.3 and now all gameobjects were erased from scene, what should I do? a two months work just vanished.
This same thing happened to me. The problem for me was that the scene just wasn’t open. Click File->Open Scene (on Windows) to open the scene you had open last time!
This happened to me as well. Went from 5.2 to 5.3 and all the elements in my heirarchy are gone and replaced with a default camera and light. My code files are still there at least.
I am on a Mac. Are you Mac or Windows?
Same here.
Lost everything. Massively disheartening as a beginner.
Plus my rotation has gone INSANE now. Had two of my mechanics, all involving rotation, working pretty nicely, now it’s all gone to hell 
Mac user here also.
My hierarchy is still intact, but I have missing scripts galore, including in assets I’ve imported from elsewhere so now the fun job of piecing it all back together. A lot of settings and links between components and game objects just gone…