How do I create the Public Folder mailbox on Office 365?
Log in to the Microsoft Office 365 portal as the user in the migration project. Make sure the user is an administrator. (You can easily tell, as there will be an Admin tab present in the upper right menu).
If the user is not an admin, then assign the user the global admin role.
From the Admin tab, select Exchange. Click on the Public Folder option in the left panel. Click on the Public Folder Mailboxes topic in the top menu.
Create a Public Folder mailbox to hold the Public Folders being migrated.
Click on the Public Folder topic in the top menu. Click on the ... (More) button from the set of actions, and then select Root Permissions. Make sure that the admin user is listed as an owner.
If the admin user is not listed as an owner, then add them and apply the change to all subfolders.
Make sure there is an Outlook tab.
If there is no Outlook tab for the admin user, then assign the user an Office 365 license.
Verify the mailbox can be viewed by clicking on the Outlook tab.