Send & Receive Issues

How to Manage and Archive a Full Microsoft 365 Group Mailbox

Maira Mehtab Sep 22, 2026 869 views

Question details

The user needs to know how to manage, clear, or archive messages when a Microsoft 365 group mailbox reaches its maximum storage limit.

Product: Microsoft 365
Device & OS: not provided
Scenario: A Microsoft 365 group mailbox has reached its capacity, and the standard procedures for clearing or archiving the group messages are unclear.
Observed behavior: The group mailbox is full, preventing it from functioning normally, and the user requires administrative tools and guidance on mailbox statistics, permissions, and message-removal options.

Before you start

Ensure you have Exchange Online Administrator or Global Administrator privileges, as managing Microsoft 365 group mailbox sizes and retention policies requires specialized administrative permissions.

Solution 1Recommended

Check Mailbox Statistics and Manually Remove Content

Use Exchange administrative tools to identify how much space is being used and manually delete unnecessary messages to free up capacity.

Group mailboxes have a strict storage limit. An Exchange administrator must review the current usage statistics to identify large attachments, outdated threads, or unnecessary system messages that are consuming space.

Access Exchange Admin Center

Log into the Microsoft 365 admin center as an Exchange Online administrator and navigate to the Exchange admin center.

Review Group Mailbox Usage

Check the mailbox statistics for the affected Microsoft 365 Group to identify what is taking up the most storage space.

Delete Unnecessary Messages

Use approved administrative tools or PowerShell commands to permanently remove unnecessary content, large attachments, or outdated emails from the group mailbox.

Important: Deleting messages from a Group mailbox is permanent. Ensure you are following your organization's data governance policies before removing content.

Solution 2

Configure Microsoft Purview Retention Policies

Set up automated rules in Microsoft Purview to retain or delete messages over time, keeping the group mailbox well within its size limits.

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Frequently Asked Questions

What is the storage limit for a Microsoft 365 Group mailbox?

By default, a Microsoft 365 Group mailbox has a strict storage limit of 50 GB. Once this limit is reached, the group cannot receive new messages until existing content is deleted.

Can I increase the size limit of a Microsoft 365 Group mailbox?

No, the 50 GB capacity limit for Microsoft 365 Group mailboxes is a hard limit set by Microsoft and cannot be increased. You must manage its size by deleting content or applying retention policies.

What happens when a Microsoft 365 Group mailbox becomes completely full?

When the mailbox hits its 50 GB limit, it stops receiving new emails. Anyone who attempts to send an email to the group will receive a Non-Delivery Report (NDR) indicating that the recipient's mailbox is full.

Can regular members delete messages to free up space in a group mailbox?

Typically, only group owners or Exchange administrators have the necessary permissions to permanently delete messages from the group mailbox. Regular members generally cannot perform administrative cleanups.

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