Inbox full but isnt, have I been hacked?

Question

Hi, I think my Outlook account may have been hacked. I cannot send emails and they remain in my outbox even though I believe I have deleted all of my inbox and deleted items. When I come to send an email the Inbox claims to still be full. Can you advise please?

Answer 1

Hi, I understand why this feels like a hack, but this issue is usually caused by account sync or mailbox status not updating. Are you seeing this in the web version of Outlook or only in the app?

If your inbox shows full even after deleting emails, the mailbox status may not have refreshed.

Sign in to Outlook on the web, then sign out of all sessions from your account security page, and sign back in on one device first.

This forces the mailbox to resync and update its storage status.

If you use the Outlook app, remove the account and add it back after doing this. Also check your recent activity page for any unknown sign-ins. If there are none, this is not a hack but a sync issue blocking sending.

Answer 2

Outlook.com is likely blocking sending because overall Microsoft cloud storage or mailbox storage is still full, even if most messages appear deleted.

Try these steps in order:

1. Check Microsoft cloud/mailbox storage
   • If Microsoft cloud storage is full, sending and receiving email is blocked and messages to the account can bounce and be unrecoverable.
   • Use the mailbox storage page linked from the article to see what is taking up space and free it where possible.
2. Empty folders that still count toward quota
   • In Outlook.com, right‑click Junk Email and select Empty folder.
   • Also empty Deleted Items/Trash (items may still be there even if the Inbox looks empty).
   • Check other large folders (Sent Items, Archive, custom folders) and delete or move old mail as needed.
3. Check for stuck or oversized messages
   • Look in Drafts and Outbox for messages that are stuck.
   • If a stuck message has attachments larger than 25 MB, remove the attachment, or upload the file to OneDrive and send a link instead, then try sending again.
4. If using Outlook on PC/Mac with an Outlook.com account
   • In Outlook desktop, select Send/Receive > Send/Receive All Folders to force a sync after freeing space.
5. Confirm account access is OK
   • If storage is not full and sending/receiving still fails, check whether the account has been blocked due to unusual sign‑in activity and follow the steps to unblock it if needed.

None of these steps by themselves prove hacking. Signs of compromise would include unknown forwarding rules, unknown sign‑ins, or messages sent that were not written by the account owner. If those are seen, follow Microsoft’s hacked/compromised account recovery guidance.

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References:

• Can't send or receive email in Outlook.com
• Outlook email stuck
• I can't send or receive messages in Outlook