How to Give permissions to a User's mailbox to Others in Office 365.
Sometimes there is a need for others to access a user's mailbox in Office 365. For example, when an employee leaves or will be away from the organization for a long period of time, access to their mailbox may be required by other members of their team for smooth business continuity.
Another example is when the manager's assistant needs to access the manager's mailbox and send mail as him/her or on their behalf. These people are often called the "delegate" (or "assistant") and the "delegator" (or "Manager" or "Mailbox Owner"), respectively.
This guide contains instructions on how to give "Read and Manage" and/or "Send As/Send on Behalf" permissions on a user's mailbox to another user in Microsoft 365 (Office 365)*
* Important: Accessing another user's mailbox may be necessary, but it is important to note that accessing another user's mailbox without proper authorization is a breach of privacy and may violate organizational policies, legal regulations, or compliance standards. Therefore, any access to user mailboxes should be done in accordance with company policies, with appropriate permissions and documentation.
How to Grant "Read and Manage", "Send as" or "Send on Behalf" permissions to an Office 365 Mailbox to Other Users of the Organization.
Assigning delegation rights to a user's mailbox to another user in Office365 can either be done through the Office 365 Admin Center, the Exchange Online Admin center or though PowerShell.
Method 1. Manage Mailbox Permissions in Office 365 Admin Center.
To give to an Office 365 user access to another user's mailbox or to share a user's mailbox with other users:
1. Login to Office 365 Admin center.
2. Go to Users > Active Users, and then click the user whose mailbox you want others to have access to.
3. Click the Mail tad and then under Mailbox Permissions click Read and manage permissions.
4. Then click Add permissions
5. Finally select the user(s) that you want to read and manage* the selected user's mailbox and click Add.
* Note: By giving "Read and Manage" permissions to another user(s) on the selected user's mailbox, the other user(s) will be able to read and delete emails on the selected mailbox but will not be able to send emails from this mailbox.
If you want the other user(s) to be able to send emails from the selected mailbox or to "Send on behalf" of the user owns the mailbox, give to them also "Send as permissions" or/and "Send on behalf of permissions".
6. After applying the permissions to the mailbox, restart the Outlook application of the user you gave access to, and the mailbox will automatically appear in Outlook pane. If this doesn't happen, follow the instructions on this article to add manually the shared mailbox in MS Outlook or in Outlook for web.
Method 2. Assign Permissions on a User Mailbox to Other User(s) in Exchange Admin Center.
To give read, "send as" or "send on behalf" permissions to other users in an Office365 mailbox in Exchange Admin Center:
1. Login to Exchange Admin Center.
2. Select Recipients, then click Mailboxes and then select the mailbox you want to give others access to.
3. On User mailbox window, go to Delegation tab and click Edit under Read and manage (Full Access)
4. Click Add Members, choose the user(s) that you want to access and read the selected mailbox and click Save.
5. You're done! If you want to give also "Send as permissions" or/and "Send on behalf of permissions" on the selected mailbox, click the "Edit" button in the corresponding fields to add the user(s).
Method 3. Assign Mailbox Permissions to Other Users in Office 365 Exchange Online.
To give mailbox permissions to another Microsoft 365 user in Exchange Online:
1. Connect to Exchange Online from PowerShell with your O365 Admin account.
2. To grant Read and manage permissions (Full Access rights) to a mailbox to another user, issue the following command:*
- Add-MailboxPermission -Identity MailboxName -User UserName -AccessRights FullAccess -InheritanceType All
* Where:
- MailboxName: is the name or email address of the user's mailbox where the permissions are being added to.
- UserName: is the name or email address of the user who will have full access rights on the user's mailbox.
For example: If you want to give permissions to the user "user1@example.com" to access the mailbox of "user2@example.com", issue the following command:
- Add-MailboxPermission -Identity user2@example.com -User user1@example.com -AccessRights FullAccess -InheritanceType All
3. To give "Send As" permission to a user's mailbox on another user in O365, issue the following command:*
- Add-RecipientPermission -Identity MailboxName -Trustee UserName -AccessRights SendAs
* Where:
- MailboxName: is the name or email address of the user's mailbox where you want to give "Send As" permissions to another user.
- UserName: is the name or email address of the user who will have "Send As" rights from the user's mailbox.
For example: If you want the user "user1@example.com" to Send As "user2@example.com", issue the following command:
-
Add-RecipientPermission -Identity user2@example.com -Trustee user1@example.com -AccessRights SendAs
4. To give "Send on Behalf" permissions to a mailbox in Office365 to another user, issue this command:*
-
Set-Mailbox -Identity MailboxName -GrantSendOnBehalfTo UserName
* Where:
- MailboxName: is the name or email address of the user's mailbox where you want to give "Send on behalf" permissions to another user.
- UserName: is the name or email address of the user who will have "Send on Behalf" rights.
For example: If you want the user "user1@example.com" to Send on Behalf of "user2@example.com", issue the following command:
-
Set-Mailbox -Identity user2@example.com -GrantSendOnBehalfTo user1@example.com
That's it! Which method worked for you?
Let me know if this guide has helped you by leaving your comment about your experience. Please like and share this guide to help others.
Frequently Asked Questions
What are the situations when someone might need access to another user's mailbox in Office 365?
Access to another user's mailbox in Office 365 might be needed when an employee leaves the organization, is away for an extended period, or when a manager's assistant requires access to manage email tasks on their behalf.
How can I assign 'Read and Manage' permissions to another user in Office 365 Admin Center?
Log into the Office 365 Admin Center, navigate to Users > Active Users, select the user whose mailbox you want to share, then click the Mail tab under Mailbox Permissions and choose 'Read and manage permissions'. Add the user(s) you want to grant access to.
What should be considered before accessing another user's mailbox for business continuity?
Before accessing another user's mailbox, it is crucial to ensure proper authorization as unauthorized access may breach privacy, violate organizational policies, or legal regulations. Always adhere to company policies and acquire appropriate permissions and documentation.
What is the difference between 'Send As' and 'Send on Behalf' permissions in Office 365?
'Send As' permissions allow a delegate to send emails as if they are the mailbox owner, appearing to come directly from the owner. 'Send on Behalf' permissions allow the delegate to send emails on behalf of the owner, where the message will indicate it was sent by the delegate on behalf of the owner.
