How to Remove a User’s Access to Mailboxes in Microsoft 365

Methods for Removing User Mailbox Access

This article will explore how to remove user access to mailboxes, utilizing PowerShell and CoreView.

Remove Mailbox Permissions Using PowerShell

To remove permissions from a user's mailbox, or from an Exchange Server 2016, Exchange Server 2019, or Exchange Online mail user, use the Remove-MailboxPermission cmdlet.  This command allows you to revoke delegated permissions previously assigned to a mailbox, such as removing another user's full access.

For Exchange Online environments, it is recommended to use the Exchange Online PowerShell V2 (EXO V2) module, which supports modern authentication (including MFA). Legacy authentication is deprecated and should be avoided for security and compliance reasons.

Requirements and Permissions

Ensure you have the necessary permissions to execute mailbox permission changes. You can find detailed permission requirements in Microsoft's documentation.

Connecting to Exchange Online (EXO V2 Module)

If you’re working with Exchange Online, connect using the EXO V2 module as follows:

Install-Module -Name ExchangeOnlineManagement # (Run once if not installed)
 Connect-ExchangeOnline -UserPrincipalName youradmin@yourdomain.com

Syntax

Remove-MailboxPermission

Example:

Remove-MailboxPermission -Identity "CoreView Demo" -User "Test User" -AccessRights FullAccess -InheritanceType All

This example shows how to remove Test User's full access permission to CoreView Demo mailbox.

For more about the Remove-MailboxPermission cmdlet, see the Microsoft documentation.

Remove Mailbox Access in CoreView

With CoreView, you can revoke mailbox permission rights, including “Send as” permissions, that a selected user has on other mailboxes.

• Go to the CoreView portal.
• Under “ACTIONS” click on “Management actions” and choose “Mailbox”. From the various mailbox action items, choose  “Remove user access to mailbox”.

• You will see the “Remove user access to mailboxes” screen.
• Choose the delegate from whom you want to remove mailbox access.

• On the following screen, select the mailboxes from which you want to remove user access. Press “Submit”.

Other Ways to Remove Delegates in CoreView

There is another action available in CoreView to remove user access to mailboxes. For more details, please refer to the following link: How to remove delegates from mailbox.

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