When Outlook.com is not receiving emails, first check whether the missing message reached the mailbox at all. It may be in another folder, hidden by an inbox view, or absent because delivery failed. Opening Outlook.com in a browser helps you tell a mailbox problem from a mail app's sync problem.

Consumer Outlook.com mailboxes include Hotmail and Live addresses, but an Outlook desktop app can also contain unrelated personal accounts or a company Exchange mailbox. The service behind the affected address determines which settings apply. Ask the sender for the exact recipient address, the approximate send time, and any delivery failure notice before changing settings or deleting messages.

Compare Webmail with the Connected App

Sign in to the Microsoft account that owns the affected Outlook.com mailbox. Search the web mailbox using the sender's address and a distinctive subject phrase, and check that the search covers the relevant folders. If you have separate Microsoft accounts, verify which one is open rather than relying on the display name.

If the message appears on the web but not in a mail app, delivery to the mailbox succeeded. Check the app's account, folder, connection, and sync status; if you recently changed your password, complete any request to sign in again. A message that disappears from webmail after an app syncs may instead have been moved or deleted by that app, so check whether the app moved or deleted it around that time.

Check Storage and Account Access

In Outlook.com, open Settings, select Account, and then Storage. Check both email storage and Microsoft cloud storage: exceeding either limit can stop incoming mail even when the other has space. Cloud storage includes OneDrive content and Outlook.com attachments, so an email quota with room left does not rule out a storage problem.

Use the storage breakdown to identify what is taking up space, and preserve anything you need before removing it. Moving messages into Deleted Items does not immediately free their mailbox space; they continue to count until that folder is emptied or the items expire. Review its contents before emptying it, and do not treat temporary recovery options as a backup. Messages rejected because of a full quota must be resent after space is available; they will not appear automatically.

If you cannot sign in or the account is temporarily blocked, resolve that access problem first. Open Microsoft Support's account sign-in helper and follow the steps for the error you see, including identity verification when requested. Being able to open webmail does not prove that every connected app has valid credentials.

Find Messages outside the Visible Inbox

Open Junk Email and look for the missing message. For a legitimate message, select it and use Report, then Not junk, to return it to the inbox. Also open Settings, Mail, and Junk email to inspect blocked addresses and domains; remove an entry only if it incorrectly blocks the intended sender. A blocked domain can affect more than one sender address, so check the domain as well as the full address.

If Focused Inbox is enabled, check Other as well as Focused. The Other tab holds inbox messages that are not shown in Focused. Above the message list, set Filter to All if a filter is hiding read messages or other categories, and sort by date if the latest mail is not where you expect it.

Look in Archive and any custom folders used to organize incoming mail. To return an archived message to Inbox, select it, choose Move to, and select Inbox. Finding the message there confirms that it was stored in the mailbox; it does not establish which action moved it.

Check Deleted Items as well, and select Restore for a message deleted by mistake. Move wanted mail out of Junk or Deleted Items promptly because both folders have automatic cleanup. Avoid emptying either folder while searching for a missing message.

Inspect Inbox Rules and Sweep

On a computer, open Outlook.com Settings, then Mail and Rules. Read the conditions, exceptions, and actions of enabled rules that could match the missing message. Include Sweep rules in the review: a sender-specific cleanup setting may remove older messages or keep only the latest one.

For a matching inbox rule that moves mail incorrectly, use Edit to narrow its conditions or change its action, then select Save. You can instead use its toggle to pause the rule while testing. Note the original setting first so you can restore a legitimate rule if it was not responsible.

Check the order of matching rules as well. Outlook.com processes them in the listed order, and Stop processing more rules prevents later rules from acting after a match. For example, a rule that moves one sender's mail and stops processing can prevent a later folder rule from taking effect; changing the later rule alone would not address that cause.

Check Automatic Forwarding

In Settings under Mail, open Forwarding and IMAP and complete the sign-in prompt if one appears. Check whether forwarding is enabled and whether you recognize the destination. If you want forwarding to continue while keeping mail in Outlook.com, select Keep a copy of forwarded messages and save the change. If forwarding is unwanted, turn it off and select Save.

Also look for forwarding or redirection actions among inbox rules, since those are separate from the forwarding setting. An address you did not add deserves an account-security check: sign in directly to your Microsoft account, review its Security settings, and secure the account if the change was unauthorized. Merely removing an unfamiliar destination does not address possible unauthorized access.

Use Sender Evidence to Check Delivery

If the message remains missing, ask the sender to inspect any delivery failure notice. Its details may identify an invalid address, a storage rejection, or another delivery problem that an empty inbox alone cannot explain. When just one sender is affected and no error is visible, that sender may need help from their mail provider to investigate the attempted delivery.

After correcting an identified cause, ask for a fresh message with a recognizable subject and note its send time. Check webmail first and then the app; success confirms delivery of that test message, while a failure notice gives you new evidence to investigate. If the problem continues, select Help in webmail, enter the problem, and choose Yes under Still need help? if the suggested answers do not resolve it. Give support the relevant addresses, time and time zone, and error text, keeping passwords and one-time codes private.