Why has my level that i have worked on for a long time went completely black i have all my assets and blueprints but it looks like this.
Have you been using streaming at any point?
If that’s the case, open the ‘levels’ window and click the eye next to the level name.
Have you set the editor Startup Map in Project Settings->Maps & Modes. The map specified within that tab is with what the editor starts up. Your Map with which you were working should be saved within the Content Browser.