Mailbox delegation is one of the most frequently performed tasks in Microsoft Exchange Online, forming the backbone of many collaborative workflows. Granting Full Access allows administrators to extend mailbox control to other users, enabling efficient handling of emails, calendars, and folders across roles and teams.
However, despite its importance, the process is not without friction. This article walks through not just how to grant Full Access, but also how to do it in a way that’s efficient, scalable, and far less frustrating in day-to-day administration.
What is Full Access Mailbox Permission in Exchange Online
Full Access lets someone open another person’s mailbox and do pretty much everything the owner can do: read emails, move things around, delete messages, manage folders. What it doesn’t do is let them send email as that person. For that, you’d also need Send As or Send on Behalf permissions. You’ll typically need this for situations like:
- An executive assistant who needs to manage their manager’s inbox day-to-day.
- A shared team mailbox that multiple people need to dip into.
- Accessing a former employee’s mailbox after they’ve left the company.
- Covering for someone who’s on leave and needs a colleague to keep things moving.
Different Ways to Grant Full Access Permission to Another Microsoft 365 User
To grant Full Access (also known as Read and manage) permissions to an Exchange Online mailbox, you can use the Exchange Admin Center (EAC), the Microsoft 365 Admin Center, or PowerShell.
Method 1: Using the Exchange Admin Center
This is the standard method for managing detailed mailbox delegations.
- Sign in to the Exchange Admin Center.
- Navigate to Recipients > Mailboxes.
- Select the mailbox you want to share.
- In the properties pane that opens, click the Delegation tab.
- Under Read and manage (Full Access), click Edit.
- Click + Add members, select the user(s) you want to grant access to, and click Save.
- Confirm the changes when prompted. It may take up a few minutes for these changes to propagate.
Method 2: Using the Microsoft 365 Admin Center
This method is often quicker for simple user management.
- Go to the Microsoft 365 Admin Center.
- Navigate to Users > Active users.
- Select the user whose mailbox you want to grant access to.
- Go to the Mail tab and click Manage mailbox permissions (or Read and manage permissions).
- Select Add permissions, choose the delegates, and click Add.
Honest Downsides of using Admin Centers:
In both the Microsoft 365 Admin Center and the Exchange Admin Center, managing mailbox permissions can become time-consuming, especially in large tenants. The process is limited to one mailbox at a time, with no support for bulk actions. Advanced settings like automapping aren’t available in the UI and require PowerShell, and in some cases, permissions may appear as GUIDs instead of user names, adding extra steps to identify access.
Method 3: Using PowerShell
PowerShell is the best option for bulk actions or when you want to disable AutoMapping (which prevents the mailbox from automatically appearing in the delegate’s Outlook). Before proceeding further, you need to connect to the Exchange Online PowerShell module.
Granting Full Access with Automapping On:
Automapping means the shared mailbox will show up automatically in the delegate’s Outlook. Handy for users, but it can slow Outlook down if you have too many shared mailboxes loading at once.
Add-MailboxPermission -Identity "TargetMailbox" -User "DelegateUser" -AccessRights FullAccess -InheritanceType All Granting Full Access with Automapping Off:
Better for shared or resource mailboxes, or when you’d rather let the user add it manually in Outlook themselves.
Add-MailboxPermission -Identity "TargetMailbox" -User "DelegateUser" -AccessRights FullAccess -AutoMapping $false Replace TargetMailbox and DelegateUser with the respective email addresses or aliases.
Check Who Already Has Full Access in Exchange Online:
Run this command to see who has Full Access to a specific mailbox.
Get-MailboxPermission -Identity "MailboxName" | where {$_.AccessRights -like 'FullAccess'} | Select-Object User, AccessRights Note: You may see “Inherited” permissions from system accounts; focus on specific user UPNs.
Remove Full Access Permission in Exchange Online:
When delegation is no longer needed, run this command to revoke access for a specific user:
Remove-MailboxPermission -Identity "MailboxName" -User "DelegateUser" -AccessRights FullAccess -InheritanceType All While PowerShell is highly capable, it introduces its own challenges. It requires familiarity with command syntax, careful execution to avoid errors, and validation before deployment in production environments. For many administrators, especially those managing permissions frequently, this can become time-consuming.
Simplify Exchange Online Mailbox Delegation with EasyEntra
If you’d rather not deal with PowerShell syntax or the sluggishness of the EAC, EasyEntra handles this from a straightforward UI panel.
Here’s how it works:
- Open the User properties panel for the mailbox owner.
- Click the Mailbox tab and select Mailbox Delegation.
- Under Full Access, click Edit and add the delegate.
- Flip the Automapping toggle to whatever you need.
- Click OK and select Apply to get the changes reflected.
What makes this especially efficient is that you’re not limited to just Full Access. In the very same panel, you can also configure Send As and Send on Behalf permissions, eliminating the need to jump between different settings or tools. This unified approach significantly reduces the time spent managing mailbox access.
For step-by-step instructions and deeper guidance, you can refer to the following resources:
- Send As permissions: https://easyentra.com/knowledge-base/how-to/how-to-delegate-send-as-permissions/
- Send on Behalf permissions: https://easyentra.com/knowledge-base/how-to/how-to-delegate-send-on-behalf-permissions/
Another major advantage is the ability to perform bulk actions. Instead of repeating the same steps for each user, you can select multiple users at once, open their properties, and apply delegation settings in a single flow. This is particularly valuable in larger environments, where consistency and speed are critical.
And finally, when it comes to copying mailbox permissions, what is usually a tedious, manual process, often involving scripts, becomes incredibly simple. With EasyEntra, you just select the source mailbox, copy delegate permissions using Ctrl + C, then select the target mailbox and paste with Ctrl + V. That’s it, done in seconds, with no complexity involved.
Overall, EasyEntra transforms mailbox delegation from a repetitive, time-consuming task into a quick and intuitive experience!
