How to add a shared mailbox as additional account in Outlook

Shared mailboxes are just one of the many great collaboration features of Exchange, and probably the most used one. There is a lot of information about them on the web, for example this TechNet article. Unfortunately, there are still some common misconceptions around them, especially when it comes to ‘missing’ functionality.

Most of those issues are caused by the fact that the shared mailbox is added as additional mailbox or automapped to the primary user mailbox. Outlook however will only expose certain features when the mailbox is added as normal (primary or additional) account. Example of such features/functionality include: Search, Inbox Rules, OOF replies, Categories, To-do lists. Other features will simply not work as expected, for example Private Items, Send on behalf/send As permissions. Another example of why you would need to add a shared mailbox as additional account includes the situation when you would like to perform a Mail Merge and send the messages using the shared mailbox account. This article will guide you on how to add a shared mailbox as a fully functional additional account in the same or new Outlook profile.

First of all, forget about accessing the mailbox directly, it is not possible (anymore). When a shared mailbox is created, a special flag is set on the associated object in AD (ExchangeUserAccountControl), which will prevent you from logging in to that mailbox. In addition, the corresponding user object is automatically created, so credentials are hidden from you. As the administrator you can of course change the credentials, apply a license to the user and try to access OWA/Outlook. Keep trying, it is not possible (anymore) 🙂

So how do you actually access the shared mailbox? The answer is, you need to be granted permissions, much like accessing another user’s mailbox. Full access, with or without Automapping, and recipient permissions in case you need them. The article above explains how you can add those, so I wont bother with the details.

Once the relevant permissions have been assigned, go to Outlook, File, Add Account:

You will be prompted by the familiar Add New Account wizard. Enter anything you want for the name of the Account, and fill in the email address of the shared mailbox. Leave the password fields blank:

Continue to the next screen and wait for the password prompt to appear. This is the important part: once the prompt shows, make sure to enter YOUR user principal name and YOUR password:

In same cases the same prompt might appear a second time, even though you have provided the correct credentials. Just enter your username and password one more time, and provided you have the necessary permissions, the shared mailbox will be added as additional account:

You can then simply press the Finish button to complete the process or configure any additional settings as necessary. If Outlook asks for credentials once you restart the client, make sure to again provide YOUR username and YOUR password.

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22 Responses to How to add a shared mailbox as additional account in Outlook

  1. bpchia says:

    Thank you for your info to add shared mailbox.

    but there are machine after setup this shared mailbox,
    i got the error message when sending email: data file cannot be accessed

    3 windows 10 machines & outlook 2016 no problem
    1 windows 7 machine & outlook 2016 got this ‘data file cannot be accessed’ problem

    I had search over google but most solution are not for ‘shared maibox’ data file,
    anyone can help? tqvm

    • Vasil Michev says:

      That’s usually caused by broken Outlook profile or some additional software locking the files up. Try Outlook in safe mode, disable any AV and other types of scanning/backup software and see if it happens again, or recreate the profile if needed.

  2. Tanya says:

    I have done this and changed the default address to the shared account before doing a Word mail merge to email. However, it uses my personal account, even though it is not the default. If I disable send/receive so I can change the From to the shared account, the email moves from my outbox to the shared outbox and gets stuck, with a similar error as mentioned above. I found on another site that it has to do with the default data file, which I can’t change as an end user in my company.

    The weird thing is, if I reply to one of the sent emails, it shows replying to the shared email address rather than mine. So it’s half right?!

    Any other suggestions?

    • Vasil Michev says:

      What you are describing sounds like the “additional mailbox” scenario, not “additional account”. Perhaps you had the shared mailbox added beforehand, or it’s automapped?

  3. Tanya says:

    Afraid it’s all greek to me as I am end user and don’t have access, etc. to the admin side. Basically no matter what I’ve tried as a user, the merge to email doesn’t work with anything but my main email address 🙁

  4. Tanya says:

    From the IT guy: ..the only data file we use is the built in one for the first.lastname email……We no longer have separate or multiple .pst files associated with Outlook. The data file settings aren’t admin protected but since there are none associated with the email, you don’t have anything there.

    • Vasil Michev says:

      What do you see under File -> Account Settings -> Account setting? Both yours and the shared mailbox should be visible there, as well as their corresponding data files.

      Come to think of it, might be easier for you to just create a new Outlook profile (Control panel -> Mail -> Show profiles -> Add) and only add the shared mailbox in it.

  5. Tanya says:

    Update: It appears to be working. When I received a reply back from one of the emails, the ‘From’ part was the shared email, rather than mine, even though the copies in my sent folder did not read that way. So it actually was working correctly.

    Now if I could add a CC email from the Excel file, it would be even better and save me duplicating my efforts.

    Thanks for responding! I don’t think I have permissions for adding profiles, because of no pst files on our system.

  6. Joe Gallant says:

    Absolutely fantastic suggestion, thank you so much for this.
    Would definitely recommend setting up an additional profile to avoid confusion!

    Thanks again, indebted to your help here.

  7. Shilpi says:

    I have followed the above steps to add additional email account and set that as default. When I click on new message, it by default selects the shared mailbox in From field.
    However the mail merge still sends out mails from my personal email id. Any suggestions on what could be missing? I have admin rights over the shared mailbox that I’m trying to use.
    Tried everything from adding another mailbox profile from control panel – Mail – Show profile and using that while starting up outlook. Even that does not work. Any help is appreciated.

    • Vasil Michev says:

      For Mail merge to work, the account needs to be set as the Default one in the profile. So add the Shared mailbox as detailed above, but also make sure that the mailbox is configured as the default one. Or simply create a new profile with the shared mailbox only (no other accounts).

  8. Eli says:

    Does this get added to Outlook as an Exchange account or IMAP?

  9. Carlos says:

    Hey Vasil,

    We’ve also been doing this for a while, just thought i’d let you know one of the major limitations we have with this :

    This is completely unsupported by MS, and if you go in to hybrid with EXO, and start migrating you will have some major issues with modern authentication during migration.

    Apart from enabling all the features as we want, MS doesn’t like this 🙁

    Best,

    Carlos

    • Carlos says:

      Forgot to say, it can also trigger large amount of account locks on shared mailboxes due to the 401 of the autodiscover for the on-prem request in hybrid, which redirects with a needcred tag to EXO generating the popup.

  10. Alexandra Rico-Lloyd says:

    Any suggestion as to how to do this when using Outlook for Mac?

  11. Victoria says:

    Hi, One of my managers at work has access to a shared mailbox (it’s a time off request mailbox shared with all of the other managers). When she responds to an email it defaults to the shared mailbox email address as the sender. When she clicks to send it from herself, she has to search for her name each and every time, it doesn’t come up automatically when she clicks to add herself. Other managers have it as an automatic prompt, as if it remembers that they had requested to have an email sent from their personal email within the box before. She never gets that alternate user dropdown when working in the shared mailbox. She always has to search for herself with each and every email. Any idea how to add her, so she no longer has to search like that anymore?

    • Vasil Michev says:

      The send/compose behavior depends on how the mailbox is added in Outlook. If the mailbox is automapped or added as additional account, the delegate name will always be selected when composing new messages. If the mailbox was added via the method described above, it will default to the mailbox address instead.

      You might also want to check the “Always use the default account when composing new messages” option under File -> Options -> Mail -> Send messages.

  12. Wardah says:

    THANKS ALOT it saved alot of time. i was trying to enter the shared mailbox when prompted and this issue kept going on for ages till i saw this

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