Sending, receiving, and organizing email in Outlook on the web for business
Follow these steps in Outlook on the web to actually free up mailbox space when normal deletion does not seem to work:
- Check storage and use the built‑in cleanup tools
- At the top of Outlook on the web, select Settings > Account > Storage.
- On the Storage page, review the breakdown of how much space each folder is using.
- In the Clean up Mailbox section, use the options to permanently delete all items (or items older than 3, 6, or 12 months) from large folders.
- Empty Deleted Items (counts against your quota)
Even if messages are “deleted” from Inbox, they still consume space while in Deleted Items.- Go to the Deleted Items folder.
- Select Empty folder or select all items and delete them.
- To permanently delete selected messages immediately, select them and press Shift + DEL on the keyboard.
- Verify that Deleted Items is now empty.
- Empty Junk Email
- Go to Junk Email and select Empty folder.
- Items in Junk are auto‑deleted after 30 days, but emptying it now frees space immediately.
- Delete large messages and attachments correctly
Attachments use mailbox storage; deleting only the file preview is not enough.- Sort folders by size or use the large‑items view from the storage page.
- Delete messages that contain large files or photos.
- Then go to Deleted Items and delete them again so they are removed permanently.
- For sent attachments, open Sent Items, delete the messages with large attachments, then clear them from Deleted Items.
- Use Sweep and Archive, then clear Deleted Items again
- In Inbox, select a message from a sender with many emails and choose Sweep to remove or keep only the latest messages.
- Remember: items deleted using Sweep still count toward storage until they are removed from Deleted Items, so empty Deleted Items again after using Sweep.
- Optionally move older mail to an archive mailbox if available, as described in the storage‑limits article.
- If storage still shows full
- Confirm that the storage indicator you are looking at is for the correct mailbox (work/school account) and not for OneDrive.
- If, after cleaning and emptying Deleted Items and Junk Email, the mailbox is still near quota, contact the organization’s IT admin and ask them to review and, if appropriate, increase the mailbox size using Exchange Online settings.
These steps ensure messages are not just moved between folders but actually removed from the mailbox so the storage number changes.
References: