If you’re seeing a warning that your mailbox is full or almost full, it means you’re approaching or have hit your storage limit. When this happens, you may not be able to send or receive emails until you free up space.
Check your mailbox size
Outlook on the web
- Click the settings icon (gear) in the top right.
- Select General > Storage.
- You’ll see how much of your mailbox storage is in use.
Outlook on Windows
- Right-click your mailbox name in the left pane and select Data File Properties (or Folder Properties).
- Click Folder Size to see a breakdown by folder.
Free up space
Start with the folders that usually take up the most room:
- Deleted Items: Right-click the Deleted Items folder and select Empty Folder. These are already deleted emails taking up space unnecessarily.
- Sent Items: Old sent emails with large attachments are a common culprit. Sort by size and delete anything you no longer need.
- Junk Email: Right-click and empty this folder regularly.
- Large attachments: Search your mailbox for large emails by typing size:>10MB in the Outlook search bar (desktop) or using the filter options in Outlook on the web. Delete or save the attachments elsewhere, then delete the emails.
Use the Archive folder
If you want to keep emails but move them out of your main folders, use the Archive folder. Select an email and press Backspace (Windows) or Delete (Mac), or click the Archive button in Outlook on the web. Archived emails still count towards your storage, but they keep your Inbox and working folders clean.
If you’re still stuck
If you’ve cleaned up and you’re still hitting the limit, raise a support ticket. We can review your mailbox, check whether a larger storage allocation is available, or help identify what’s using the most space.
Mailbox full and can’t send or receive? Raise a support ticket and we’ll help you get it sorted quickly.