If you have access to a shared mailbox, you may have noticed that searching within that shared mailbox from your personal account does not return the expected results.
There are numerous articles online detailing issues with searching in an auto-mapped shared mailbox.
Our advice would be to search through a shared mailbox in one of two ways.
1) Access the shared mailbox through your web browser. You can do so by following the instructions in the link below.
How to access a Shared Mailbox through Outlook on the web
2) Add the shared mailbox as a separate profile in your Outlook application. You can do so by following the instructions in the link below from ‘Now that I have the correct access to the Shared Mailbox, what should I do?’ onwards.
How to perform a Mail merge using a Shared Mailbox
Either of these methods will provide you with direct access to the shared mailbox from which you can perform your search.