How to access an Exchange Online mailbox without a license

An Office 365 or Microsoft 365 Admin will hopefully have a separate admin account to perform higher level (privileged) tasks, compared the their standard user account.

As a result, admin accounts should not need any license, because they are not used as a normal user. A person should not need to have two sets of licenses – but there are a few problems that may arise because of this.

For example, if you want to use your administrative account to access another users mailbox, that can be difficult when you don’t have a mailbox to access, then open another user mailbox. Outlook can be used to work around this, where you set up a profile for the user’s email address you want to access, but enter administrator credentials when requested (total overkill!)

adding anohter mailbox to outlook (overkill!)

Your Name is just a display name field, email address needs to be the user’s email. Don’t enter a password here and click ‘Next’..

Login using Admin account

This login page will start by showing the user’s email address, use the option ‘Sign in with another account’ and use your admin account.

If you can’t get in, add the required privileges and try again (it always takes a few minutes for the changes to the permissions to take effect.. – so be patient)

# Connecting to Exchange online
Connect-ExchangeOnline -UserPrincipalName

# Add permission to access all UserMailboxes, Admin excluded
Get-Mailbox -ResultSize unlimited -Filter {(RecipientTypeDetails -eq 'UserMailbox') -and (Alias -ne 'Admin')} | Add-MailboxPermission -User -AccessRights fullaccess -InheritanceType all

The above works well, but it’s a little time consuming if you’re accessing a mailbox for a quick check.

If you try to go to Exchange/Outlook Online, you’ll get a message saying your admin account doesn’t have a license or a mailbox.

To get around this, you’ll need to use a URL like:

if you want the ‘new’ Outlook.

It will then jump straight to that user’s mailbox, assuming you have access rights to it, and have waited a few minutes for the rights to apply.

Using the URL method is really quick way of accessing another user’s mailbox without needing a license yourself.

As always, feel free to comment..