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How to Find Shared Mailbox Access in Exchange Online via PowerShell

Huda Qurayshi Sep 30, 2026 869 views

Question details

The user needs to identify which shared or additional mailboxes a specific user has delegated access to in Exchange Online.

How to Find Shared or Additional Mailbox Access in Exchange Online

Product: Exchange Online
Device & OS: not provided
Scenario: Checking mailbox delegation and access permissions for security auditing or user management purposes.
Observed behavior: Standard recipient type details in the admin center do not reveal all delegated mailbox access, requiring a script to list comprehensive permissions.

Before you start

Ensure you have the Exchange Online PowerShell module installed on your computer and possess the necessary administrative privileges (such as Exchange Administrator) to query mailbox permissions.

Solution 1Recommended

Use Exchange Online PowerShell to Check Mailbox Permissions

Connect to Exchange Online using PowerShell and run the Get-MailboxPermission cmdlet to retrieve and export delegated access rights.

Because recipient type details alone may not show all delegated mailbox access, PowerShell is the most reliable method to audit who has access to which mailboxes in your tenant.

Connect to Exchange Online

Open PowerShell as an administrator and type 'Connect-ExchangeOnline' to authenticate with your Microsoft 365 admin credentials.

Run the Get-MailboxPermission cmdlet

To check permissions across user and shared mailboxes for a specific target user, use the command: 'Get-Mailbox -RecipientTypeDetails UserMailbox,SharedMailbox | Get-MailboxPermission -User <TargetUserEmail>'.

Export the results to CSV

To make the data easier to read and share, pipe the output to a CSV file by appending the export command: '| Select-Object Identity, User, AccessRights | Export-Csv -Path C:\MailboxAccess.csv -NoTypeInformation'.

Use Exchange Online PowerShell to Check Mailbox Permissions

Empty Results: If the command returns an empty result, it means there is no delegated mailbox access configured for that specific user.

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Easily Analyze Exported Exchange CSV Reports with WPS Office

While Exchange Online requires PowerShell for administrative queries, handling the exported CSV reports and everyday office tasks is easier with WPS Office. It is a free, lightweight, and highly compatible alternative to Microsoft Office.

1. Download and Install WPS Office: Visit the official WPS Office website to download and install the free suite on your computer.
2. Open Your CSV Report: Launch WPS Spreadsheets and navigate to the directory where you saved your Exchange Online CSV export.
3. Analyze the Data: Use built-in data filters, formatting, and analysis tools to easily review the delegated mailbox access rights.

Seamlessly open, edit, and filter exported CSV mailbox reports.Fully compatible with Microsoft Excel, Word, and PowerPoint file formats (.xlsx, .docx, .pptx).Lightweight installation ensures fast loading times and smooth performance on any device.Familiar user interface requires zero learning curve for users switching from Microsoft Office.

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Frequently Asked Questions

Why aren't all delegated mailboxes showing up in the Microsoft 365 Admin Center?

The Microsoft 365 Admin Center graphical interface may not display full delegation details depending on how permissions were historically granted. PowerShell provides a raw, comprehensive view of all assigned permissions at the server level.

What permissions do I need to run Get-MailboxPermission?

You need to be assigned the Organization Management or Recipient Management administrative role within Exchange Online to successfully run this cmdlet and view permissions for other users.

Can I check mailbox delegation permissions for all users at once?

Yes, you can run a script that iterates through all mailboxes in your organization without specifying a target user, and exports all access rights. Note that this may take a significant amount of time to process in large enterprise environments.

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