I have a Core i7 laptop with 8GB ram with a not worth mentioning gpu. I just wanted to say that if you have low specs machine like this, the editor will open but it will take a very long time. At the end committed memory in Task Manager was 17GB/23GB on a 8GB machine.
The first thing I did was create a new empty level in Project Settings > Map & Modes and set default map to the new empty level. Now the project opens instantly.