Dear Patrick Downes,
Good day!
Thank you for posting to Microsoft Community. We are glad to assist.
Based on your post regarding with "Shared address book problem with Outlook 365". To get the shared address book for being your default kindly try below method check if it will help:
- On the Home tab, in the Find group, click Address Book.
- Click Tools --> Options and select Custom.
- Click the up
and down
arrows next to the list to move your address books then choose your shared address book. - Click OK.
For extra reference kindly refer to below articles:
I hope the above information will be helpful. Please feel free to let me know if there are any updates or if I've got you wrong. I will keep assisting you based on the information you provide. We sincerely appreciate your patience and cooperation.
Thanks for your precious time.
Have a nice day!
Best regards,
Inema | Microsoft Community Moderator