Every project gets stuck on 39%

Agreed, @IndieGameCove. Often this just means the editor/engine is compiling shaders for the first time, and once it finishes, the next times the editor is opened, it will open very quickly.

If you’re ever uncertain whether the editor is “broken” during startup, or whether it’s just quietly compiling shaders or doing work in the background, you can check your Task Manager (or equivalent on other operating systems) to take a look at how much CPU resources the editor is using. If the editor is unresponsive but is consuming some significant CPU cycles, try to wait it out and see if it eventually opens. (In my experience, it always does eventually!)