How To Cleanup Storage Space in Microsoft 365 Email

📫 Mailbox Storage Limits in Outlook

If your mailbox is nearing its maximum capacity, you will receive email and in-app notifications warning you that your storage is almost full. Once the storage limit is exceeded:

You won’t be able to send or receive emails.

Senders will receive an error message stating your mailbox is full.

🫙 Check Your Mailbox Storage

For Outlook Web App (Office 365 & Small Business)

Click the Settings (⚙️) icon at the top of the page.

Navigate to General > Storage to view usage details.



For New Outlook for Windows

Click the Settings (⚙️) icon at the top of the page.

Go to Accounts > Storage to check storage usage.

🧼 Clean Up Your Mailbox

From the Storage page, you'll see a breakdown of how much space each folder is using.

Below the breakdown, you can:

Permanently delete all emails in specific folders.

Choose to delete emails older than 3, 6, or 12 months to free up space.

This applies to both Outlook Web App and Outlook.com storage settings.