License & Subscription Issues

How to Increase Microsoft 365 Mailbox Storage Beyond 50 GB

Kushani Nimanthika Oct 10, 2026 869 views

Question details

An administrator needs to increase a user's Microsoft 365 mailbox storage capacity beyond the default 50 GB limit.

How to Increase Microsoft 365 Mailbox Storage Beyond 50 GB

Product: Microsoft 365
Device & OS: not provided
Scenario: A user's primary mailbox has reached or is approaching the 50 GB capacity limit, preventing them from sending or receiving new email messages.
Observed behavior: The administrator cannot increase the mailbox quota beyond 50 GB on the current plan and needs to apply an archiving solution or subscription upgrade to resolve the storage limitation.

Before you start

Ensure you have Microsoft 365 global administrator or Exchange administrator privileges to modify mailbox limits, assign new licenses, or enable archiving features.

Solution 1Recommended

Enable an Archive Mailbox in Exchange Online

Enabling an in-place archive provides the user with an additional 50 GB (or more) of storage to move older emails, freeing up space in the primary mailbox.

Archive mailboxes provide users with a secondary storage space for their email data. Once enabled, users can manually move messages to the archive or use retention policies to move them automatically without losing access to historical emails.

Access the Microsoft Purview compliance portal

Sign in to the Microsoft 365 admin center using your administrator credentials, then navigate to the Microsoft Purview compliance portal.

Navigate to the Archive settings

In the left navigation pane, go to Data lifecycle management, select Exchange (legacy), and click on Archive.

Enable the archive for the user

Select the user whose mailbox has reached the 50 GB limit, click 'Enable archive' in the details pane on the right side, and confirm the action.

Enable an Archive Mailbox in Exchange Online

Archiving Add-on Requirements: If the user is on a Microsoft 365 Business Basic or Standard plan, the archive mailbox offers an additional 50 GB. For unlimited archiving (auto-expanding archive), an Exchange Online Archiving add-on or a premium enterprise plan is required.

Solution 2

Upgrade the Exchange Online Subscription Plan

Upgrade the user's license to a plan that natively supports a 100 GB primary mailbox, such as Exchange Online Plan 2 or Office 365 E3/E5.

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Frequently Asked Questions

Why is my Microsoft 365 mailbox restricted to exactly 50 GB?

Most standard business plans, such as Microsoft 365 Business Basic and Business Standard, run on Exchange Online Plan 1, which strictly enforces a hard cap of 50 GB for the primary mailbox.

Does auto-expanding archiving cost extra?

Auto-expanding archiving is included automatically in Exchange Online Plan 2 and enterprise plans like Office 365 E3 and E5. If you are using a base Exchange Online Plan 1 license, you must purchase a separate Exchange Online Archiving add-on to utilize unlimited auto-expanding storage.

How long does it take for the mailbox size limit to increase after an upgrade?

After upgrading a license or enabling an archive mailbox in the admin center, it typically takes a few minutes to take effect. However, depending on server sync cycles, it can occasionally take up to 24 hours for the new storage capacity to reflect in the user's Outlook client.

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