Exchange | grant read-only access to shared Mailbox (Update)

(Update) Deletable Attachments

It seems like attachments are still deletable and I didn’t find a way to prevent this. Doesn’t seem to be possible. Well, it still works in case you want to prevent the user from removing emails.

Hey there,

I want to go through the steps, to set up read-only access to a shared mailbox (or any mailbox) in Exchange. In this case Exchange Online, but it should work with the on-prem Exchange as well. I want the user to be able to read and mark emails “as read”, but not delete them.

From what I could gather, this isn’t really intuitive and requires the Powershell.

Let’s start.

Setting the permissions

First, connect to your Exchange or Exchange Online.

For the on-prem Exchange just use “Exchange Management Shell”. In the case of Exchange Online, you will need to connect to Office365 first.

PS /home/user> $UserCredential = Get-Credential
## Enter you Credentials
PowerShell credential request
Enter your credentials.
Password for user *******

## Connect to Exchange Online
PS /home/user> $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri -Credential $UserCredential -Authentication Basic -AllowRedirection

## Import the required Modules
PS /home/user> Import-PSSession $Session -DisableNameChecking

Or you could use this method. It’s easier.

“Connect-ExchangeOnline” will open the browser, where you can login with your credentials.

If you want to open a browser manually use the “-device” option. This is useful if you use something like the “Firefox Multi-Account Container” Extension.

## Install the Module
PS /home/user> Install-Module -Name ExchangeOnlineManagement

## Connect to Exchange Online
PS /home/user> Connect-ExchangeOnline

## Connect to Exchange Online with "-device"
PS /home/user> Connect-ExchangeOnline -device
To sign in, use a web browser to open the page and enter the code CFE2D8TUZ to authenticate

Next, we give the user read permission to the shared mailbox. For this example, I will use “” for the shared mailbox and “” as the user mailbox.

PS /home/user> Add-MailboxPermission -Identity -user -AccessRights ReadPermission -InheritanceType all

Now you could add the mailbox in Outlook, but the user won’t be able to see any folders. For this, we need to set the folder permission as well.

## Add permission to the root folder
PS /home/user> Add-MailboxFolderPermission -Identity\ -User -AccessRights Reviewer

## Add permission to the "inbox" folder.
PS /home/user> Add-MailboxFolderPermission -Identity\Inbox -User -AccessRights FolderVisible,ReadItems,EditAllItems

Repeat this process for every folder, you want to add the permission. The access rights combination of “FolderVisible,ReadItems,EditAllItems” should allow the user to read and mark emails, but not delete them.

Display information

Mailbox folders

To list the mailbox folders, you can use these commands.

This didn’t work for me on other mailboxes.

PS /home/user> Get-MailboxFolder -Identity -Recurse

Name                          FolderPath                              HasSubfolders
----                          ----------                              -------------
Top of Information Store      {}                                      True
Archive                       {Archive}                               False
Calendar                      {Calendar}                              True
Birthdays                     {Calendar, Birthdays}                   False

or this one. It’s not pretty but works.

PS /home/user> Get-MailboxFolderStatistics -Identity | fl FolderPath

Mailbox / Folder permissions

For the permissions on the mailbox, use this command.

## Mailbox permission
PS /home/user> Get-MailboxPermission -Identity 

Identity             User                 AccessRights                                                             IsInherited Deny
--------             ----                 ------------                                                             ----------- ----
mail NT AUTHORITY\SELF    {FullAccess, ReadPermission}                                             False       False
mail NT AUTHORITY\SELF    {FullAccess, ExternalAccount, ReadPermission}                            False       False
mail {ReadPermission}                                                         False       False

The permissions for the folders you can get with this.

PS /home/user> Get-MailboxFolderPermission -Identity\Inbox

FolderName           User                 AccessRights                                  SharingPermissionFlags
----------           ----                 ------------                                  ----------------------
Inbox                Default              {None}                                        
Inbox                Anonymous            {None}                                        
Inbox                user       {ReadItems, EditOwnedItems, EditAllItems, Fo… 

Outlook configuration

The last step is to add the mailbox to Outlook.

In Outlook click on “File”.
Info -> Account Settings -> Account Settings
Double click on the E-Mail -> More Settings -> Advanced -> Add
Enter the name of the mailbox. “Mail” in my case.

After this, the user should be able to access the new mailbox.

Adding shared mailbox to OWA

Because it came up. Here is how you can add the shared folder in OWA.

Right click on “folder” and “Add shared folder or mailbox”

This Post Has 7 Comments

  1. Matija

    Dear Gökhan,

    did you try to open the “read-only” shared mailbox over OWA in O365?


    1. Gökhan

      Hello Matija,

      unfortunately it’s been to long, so I don’t remember if it works in the OWA. This setup was mainly for a customer for a specific use case in Outlook.

      Technically it should work though, since it’s a Exchange permission setup and not on the Outlook side.

    2. Gökhan

      So, I tested it and it seems to work without any problems.
      What’s interesting is that I can’t even delete the attachments, which was an issue I couldn’t solve in Outlook.

      To assign the mailbox, right click on “Folder” and select “Add Shared Folder”. Now you can select the shared mailbox and add it to OWA.

      1. Carlos SIlva

        Mate you literally just solved my issue, I went through the steps and wasn’t finding where to add the mailbox on OWA.

        Thanks everyone.

        1. Gökhan

          Happy to help 🙂
          Thanks for the comment.

  2. Jerome

    Thanks Gökhan, this is working great on Outlook and OWA but I’m having troubles to get it worked on Outlook Mobile (iOS) using the Add Shared Mailbox option (this one : ).
    It keeps saying : “Authentication Failed, you may not have the rights permissions to add this mailbox or this mailbox or this mailbox doesn’t exist” but it works as soon as I grant full access permission via the Exchange admin portal… any idea why ?
    thank you.

    1. Gökhan

      Hello Jerome,
      Thank you for your comment. We don’t use iOS at all at work, not even with our customers, so I don’t have any experience with the operating system. This may be an issue with the application itself, but I’m not entirely certain.

      I will see if I can try it with an Android device. I think, the applications are not identical, but maybe I can find somethin, if the same issue occurs.

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