Using older versions of Outlook for Mac in business environments
Hi Central Creative,
Welcome to post in the community.
From your description, the gray scroll bar appeared. The issue could associate to the setting changed. Therefore, I suggest you first can try the OutlookResetPreferences tool to check if it is workable. Please refer to the OutlookResetPreferences part of article to use. Furthermore, please also upgrade Outlook for mac to check the result if it isn't the latest.
If you have anything unclear, please feel free to let us know.
Regards,
Joey