Accessing other people's mailboxes in Microsoft 365

Original KB number:   10048

This article explains how to assign access permissions to a user mailbox, to multiple mailboxes, and to individual users in Microsoft 365.

Who is it for?

Microsoft 365 administrators who help set up access permissions for users to open other people's mailboxes.

How does it work?

We'll begin by asking you the task you want to do. Then we'll take you through a series of steps that are specific to your situation.

Estimated time of completion:

10-15 minutes.

Welcome to the guide

Select the scenario that you are trying to configure for your users. Once you select the appropriate scenario below, the step-by-step instructions will be provided.

Which Microsoft 365 plan do you use

Select the plan that your organization subscribes to in Microsoft 365.

Not sure which Microsoft 365 plan your organization uses? Go to https://portal.microsoftonline.com and login using your Microsoft 365 administrator credentials.

How do I access the mailbox (Small Business)

Use the Exchange Admin Center (EAC) to assign permissions

The following procedure shows how to assign full permissions to a user mailbox:

Before you begin, sign in to the Exchange admin center (EAC) at https://outlook.office365.com/ecp/ using your Microsoft 365 tenant administrator credentials. As a Microsoft 365 Small Business admin, you need to access EAC by using the direct URL. The Microsoft 365 Small Business Microsoft Online Portal does not have an option to access EAC.

  1. In the EAC, navigate to Recipients > Mailboxes.

  2. In the list of mailboxes, select the mailbox that you want to assign permissions for, and then select EditEdit icon.

  3. On the mailbox properties page, select Mailbox Delegation.

  4. To assign permissions to delegates, select AddAdd icon under Full Access to display a page that lists all recipients in your Exchange organization that can be assigned the permission. Select the recipients you want, add them to the list, and then select OK. You can also search for a specific recipient by typing the recipient's name in the search box and then selecting SearchSearch icon. To remove a permission for a recipient, under the appropriate permission, select the recipient and then select RemoveRemove icon.

  5. Select Save to save your changes.

How do I access the mailbox

Depending on the email client you choose, the detailed instructions for accessing the mailbox that you have Full Access permissions to are listed below:

Outlook

If you are using Outlook 2013 or Outlook 2010, the mailbox for which you have been granted access automatically display in your folder list. In the example below, Adam Barr has been granted access to the mailbox of Kim Akers. Kim's mailbox displays automatically in Adam's folder list in Outlook 2013.

Note

If you were recently granted access to the mailbox, it may take a few hours for the other user's mailbox to display in your folder list.

other user's mailbox shown in your folder

Outlook Web App

After you complete this procedure, the person's mailbox for which you have been provided access to will display in your Outlook Web App folder list every time you open Outlook Web App.

  1. Sign in to your mailbox using Outlook Web App.

  2. Right-click your name in the folder list, and select Add shared folder.

    Add shared folder

  3. In the Add shared folder dialog box, type the name of the mailbox that you have been provided access, and select Add.

    Add a shared folder

  4. The mailbox appears in your Outlook Web App folder list.

    mailbox appears in your Outlook Web App

    If you have only been provided access to specific folders in the other user's mailbox, you will only see the folders for which you have been granted access.

If you decide that you no longer want to see the other person's mailbox every time you open Outlook Web App, right-click the folder, and select Remove shared folder.

Remove shared folder

Did this resolve your issue?

How do I access the mailbox (Enterprise, Midsize, Education)

Use the EAC to assign permissions

The following procedure shows how to assign full permissions to a user mailbox:

Before you begin, sign in to the Exchange admin center (EAC) at https://outlook.office365.com/ecp/ using your Microsoft 365 tenant administrator credentials. As a Microsoft 365 admin for Enterprises, Midsize, or Education, you can also access EAC by selecting Admin > Exchange in the Microsoft Online Portal.

  1. In the EAC, navigate to Recipients > Mailboxes.

  2. In the list of mailboxes, select the mailbox that you want to assign permissions for, and then select EditEdit icon.

  3. On the mailbox properties page, select Mailbox Delegation.

  4. To assign permissions to delegates, select AddAdd icon under Full Access to display a page that lists all recipients in your Exchange organization that can be assigned the permission. Select the recipients you want, add them to the list, and then select OK. You can also search for a specific recipient by typing the recipient's name in the search box and then selecting Search Search icon.

    The Full Access permission allows a delegate to open a user's mailbox and access the contents of the mailbox.

    Note

    Assigning the Full Access permission doesn't allow the delegate to send email from the mailbox.You have to assign the delegate the Send As or the Send on Behalf permission to send email.

  5. Select Save to save your changes.

How do I access the mailbox

Depending on the email client you choose, the detailed instructions for accessing the mailbox that you have Full Access permissions to are listed below:

Outlook

If you are using Outlook 2013 or Outlook 2010, the mailbox for which you have been granted access automatically display in your folder list. In the example below, Adam Barr has been granted access to the mailbox of Kim Akers. Kim's mailbox displays automatically in Adam's folder list in Outlook 2013.

Note

If you were recently granted access to the mailbox, it may take a few hours for the other user's mailbox to display in your folder list.

other user's mailbox shown in your folder

Outlook Web App

After you complete this procedure, the person's mailbox for which you have been provided access to will display in your Outlook Web App folder list every time you open Outlook Web App.

  1. Log in to your mailbox using Outlook Web App.

  2. Right-click your name in the folder list, and select Add shared folder.

    Add shared folder

  3. In the Add shared folder dialog box, type the name of the mailbox that you have been provided access, and select Add.

    Add a shared folder

  4. The mailbox appears in your Outlook Web App folder list.

    mailbox appears in your Outlook Web App

If you decide that you no longer want to see the other person's mailbox every time you open Outlook Web App, right-click the folder, and select Remove shared folder.

Remove shared folder

Did this resolve your issue?

Set up permissions to access multiple mailboxes

You can assign access permissions to multiple mailboxes for the entire mailbox or specific folders in the mailbox. You can also choose to assign access permissions to individual user or group.

Select if you would like permissions to be assigned on the mailbox level (access to all of the mailbox folders) or just specific folders within the mailbox (access only folders specifically shared).

How do I access the mailbox (Entire Mailbox)

Assign permissions to the entire mailbox

You may want to perform this procedure as if an administrator in your organization needs to have access to all mailboxes in the organization.

  1. Connect to Exchange Online by using remote PowerShell. For info about how to do this, go to the following Microsoft website:

    Connect to Exchange Online PowerShell

  2. Type the following command, and then press Enter:

    Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'UserMailbox') -and (Alias -ne 'Admin')} | Add-MailboxPermission -User AdministratorAccount@contoso.com -AccessRights fullaccess -InheritanceType all
    

After you perform these steps, the specified user will be able to access all user mailboxes in Microsoft 365. The user will be able to view the contents of the mailboxes from either Outlook or Outlook Web App.

For more information, see How to use Windows PowerShell to grant an admin access to all user mailboxes in Office 365.

How do I access the mailbox

You can access user's mailboxes by using Outlook or Outlook Web App. Use the following steps to open the mailboxes for which you have been granted access. Depending on the email client you choose, the detailed instructions for accessing the shared mailbox are listed below:

Outlook

If you are using Outlook 2013 or Outlook 2010, the mailbox for which you have been granted access automatically display in your folder list. In the example below, Adam Barr has been granted access to the mailbox of Kim Akers. Kim's mailbox displays automatically in Adam's folder list in Outlook 2013.

other user's mailbox shown in your folder

Outlook Web App

After you complete this procedure, the person's mailbox for which you have been provided access to will display in your Outlook Web App folder list every time you open Outlook Web App.

  1. Log in to your mailbox using Outlook Web App.

  2. Right-click your name in the folder list, and select Add shared folder.

    Add shared folder

  3. In the Add shared folder dialog box, type the name of the mailbox that you have been provided access, and select Add.

    Add a shared folder

  4. The mailbox appears in your Outlook Web App folder list.

    mailbox appears in your Outlook Web App

If you have only been provided access to specific folders in the other user's mailbox, you will only see the folders for which you have been granted access.

If you decide that you no longer want to see the other person's mailbox every time you open Outlook Web App, right-click the folder, and select Remove shared folder.

Remove shared folder

Did this resolve your issue?

Assign access to specific folders in a user's mailbox

This example assigns permissions for a user to access specific folders in another user's mailbox in an Exchange Online or Microsoft 365 environment. Do the following:

  1. Connect to Exchange Online by using remote PowerShell. For more information about how to do this, go to Connect to Exchange Online PowerShell.

  2. Enter a command using the following syntax to assign access permissions to the specific folder:

    Add-MailboxFolderPermission -Identity <SMTP address or alias of recipient> : <Folder path>-AccessRights <Permission you want to grant the recipient> -User <SMTP address or alias of recipient to be granted access>
    
  3. This example assigns permissions for Ed to access Ayla's Marketing mailbox folder and applies the Owner role to his access of that folder.

    Add-MailboxFolderPermission -Identity ayla@contoso.com:\Marketing -User Ed@contoso.com -AccessRights Owner
    

For more information, see Add-MailboxFolderPermission.

Did this resolve your issue?

The issue was not resolved

Sorry, we couldn't resolve your issue with this guide. Provide feedback on this walkthrough, and then use the resources below to continue troubleshooting.

Visit the Microsoft 365 Community for self-help support. Do one of the following:

  • Use search to find a solution to your issue.
  • Use the Help Center or the Troubleshooting tool that are both available from the top of every community page.
  • Sign in with your Microsoft 365 admin credentials, and then post a question to the community.