Hi @Joe Grover
When exporting Contacts to .CSV, internal users are not exported with their SMTP address, instead having the X500-ish address like /o=ExchangeLabs/ou=Exchange Administrative Group etc.
Did you mean you would like to export all the user mailboxes and shared mailboxes in the tenant to a PST file?
If you have the required permissions, I suppose that you may use EXO powershell to do it.
The command would be like:
Get-Mailbox -ResultSize unlimited -RecipientTypeDetails UserMailbox,SharedMailbox,RoomMailbox | Select-Object DisplayName, PrimarySMTPAddress | Export-Csv C:\temp\contoso.csv
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.