Hi @Radosław Jachymiak ,
Agreed with Schneider that you can get a copy of the folder structure using the Archive option in Outlook, and then import the PST file to the new mailbox so that the folder structure can be replicated.
You can add both mailboxes to Outlook to go through the procedures. For steps about how to add shared mailboxes to Outlook as additional accounts, you can refer to: How to add a shared mailbox as additional account in Outlook.
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
Below are some more links for reference:
- Copy the current Mailbox folder structure to a new pst-file
(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.) - Import email, contacts, and calendar from an Outlook .pst file
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