Hi Dan,
I’ve noticed the tags of this thread you posted include “Enterprise” and “15”, does it mean you’re using the Office 365 for Enterprises post-upgrade?
For post-upgrade users, Office 365 provides the Office 2013 for downloading instead of the Office 2010. Therefore, I would like to confirm where you downloaded and installed your Office 2010.
If you downloaded the Office 2010 from Office 365 online services before the Service Upgrade, it is recommended you run the desktop setup by following these steps below:
1. Sign in to your Office 365 admin center.
2. Click Download software under admin shortcuts in the upper-right.
3. Select desktop setup in the left panel and click set up button.
This will help you install any available updates to your Office.
Moreover, based on the screenshot you posted above, this is probably an Outlook client issue. In this case, if this Office 2010 of yours was not downloaded from Office 365 online services, I suggest you post this question in our Office 2010 Community. This forum is staffed with technical support engineers who can focus on client side to provide you with more professional support.
Thank you for your understanding.
Best Regards,
Allen Zhang