You're must missing Clouds? Everything else is there? It could be a corrupt preferences issue. You might want to delete them and see if fresh preferences fixes it. https://helpx.adobe.com/photoshop/using/preferences.html What OS are you on? Other than corrupt preferences or a bad install, I can't think of a reason it's greyed out. It runs on just about anything. Have you updated your OS or PS very recently? That is when things tend to become corrupt and display unexpected issues.