Hi Robert Brazeau1,
Thank you for posting in the Microsoft community. We are happy to assist.
Based on the information you have shared with us; I understand you are having issue on drag and drop emails in Outlook 2016 after updates. To fully understand the scenario, I would like to ask some questions to narrow down the situation and work toward the resolution.
Could you share with us the screenshot to show version of the affected outlook application? You can click on File >>Office Account open the version page
May I confirm if the affected account signed in to the application is an Office 365 subscription. Are you using Microsoft 365 Business Basic, Standard, Enterprise, or Education? Alternatively, is it Microsoft 365 Family, Personal, Office 365 Home and Business, Office 365 Home, and Student, or a Personal (Outlook.com, Live.com, Hotmail.com) subscription or any third-party account?
Please note that my initial response may not address your current situation immediately. However, with your help and more detailed information, we can work together to find a direction specific to your current situation.
I look forward to your next updates. Thank you so much for your precious time. stay safe and healthy.