The "Outlook is Running Slow" message can make you wonder why it’s not working well. But when we look into why this happens, we find various reasons that together make Outlook slow. We love reading your suggestions on new features and feedback about how you use our products! To learn more about how to share your feedback, see How do I give feedback on Microsoft Office. Currently, you can't use Outlook on Windows to edit calendars that are shared with your Outlook.com account, even if you've reco...