Outlook Not Receiving Emails: How to Fix It

When emails stop arriving in Outlook it can mean one of two very different things: the messages aren’t reaching your mailbox at all, or they’re arriving on the server but not appearing in Outlook. That distinction matters — the fix is completely different depending on which problem you’re dealing with. This guide walks through both scenarios, starting with the quickest checks and moving through to the less obvious causes.

First: Work Out Which Problem You Have

Log into your webmail (Outlook.com, outlook.office.com for Microsoft 365, or your host’s webmail for IMAP accounts) and check whether the missing emails are there.

• Emails are in webmail but not in Outlook: This is a sync or client-side issue. The server has the mail; Outlook isn’t pulling it down.
• Emails aren’t in webmail either: The problem is server-side — delivery failure, filtering, or the sender’s issue. Outlook itself is fine.

Step 1: Force a Manual Sync

Press F9 or click Send/Receive > Send/Receive All Folders. Watch the status bar at the bottom of Outlook — it should show download progress. If it completes without errors but new mail still doesn’t appear, move to the next step.

If you get an error during the sync, see our guide on Outlook not syncing for connection-specific fixes.

Step 2: Check Your Junk Email Folder

Outlook’s junk filter is aggressive by default. Open your Junk Email folder and look for any messages that shouldn’t be there. If you find legitimate emails being filtered:

1. Right-click the email and select Junk > Not Junk.
2. Tick “Always trust email from [sender’s domain]” and click OK.

To reduce over-filtering going forward, go to Home > Junk > Junk Email Options and consider dropping the filter level from “High” to “Low”.

Step 3: Check Your Inbox Rules

Inbox rules are one of the most frequently overlooked causes of “missing” emails. A rule set up months ago could be quietly moving, deleting, or categorising incoming messages before you see them.

1. Go to File > Manage Rules & Alerts (classic Outlook) or Settings > Rules (new Outlook).
2. Review every rule carefully — look for any that move mail to a specific folder, mark as read, or delete.
3. Temporarily disable all rules and ask someone to send you a test email.

Also check your Other tab if you’re using a Microsoft 365 account — the Focused Inbox feature splits your inbox into “Focused” and “Other”, and emails landing in the Other tab can feel like they’ve gone missing.

Disable Focused Inbox

Go to View > Show Focused Inbox and toggle it off. All mail will then land in your main Inbox.

Step 4: Check for a Full Mailbox

When you hit your storage limit, incoming mail bounces back to the sender — you won’t receive it, and you may not get any notification. Check your mailbox size in Outlook: File > Tools > Mailbox Cleanup > View Mailbox Size.

If you’re near the limit, empty your Deleted Items and Junk Email folders, then archive older emails. See our guide on fixing a full Outlook mailbox for more detail.

Step 5: Check Your OST File and Local Cache

Outlook stores a local cached copy of your mailbox in an OST file. If this becomes corrupted, new emails may not appear even though they’re on the server.

1. Close Outlook.
2. Navigate to %localappdata%MicrosoftOutlook in File Explorer.
3. Find the .ost file for your account and rename it to yourname.ost.old.
4. Reopen Outlook — it will create a fresh OST file and re-sync from the server.

Step 6: Check Server-Side Rules and Filters

If you use Microsoft 365 or Exchange through an organisation, rules can also exist server-side. Log into Outlook on the web, go to Settings > View all Outlook settings > Mail > Rules and check for any rules you didn’t set up. Also check Sweep rules — these can automatically delete or move emails from specific senders on a schedule.

Step 7: Check Whether Emails Are Arriving at All

If emails aren’t appearing in webmail either, the problem is upstream of Outlook entirely. Common causes:

• Full mailbox — senders get a bounce if your mailbox is full.
• Domain or DNS issue — if your domain’s MX records have been changed or expired, email won’t route to your mailbox. Check your MX records using MXToolbox.
• Account suspended — if your Microsoft 365 subscription has lapsed, your mailbox may be disabled.
• Sender-side issue — ask the sender to check for a non-delivery report (NDR) in their sent items.

Step 8: Check Server-Level Spam Quarantine

Microsoft 365 has server-side spam filtering (Exchange Online Protection) that can quarantine legitimate emails before they reach your mailbox. If you have admin access, check the quarantine at security.microsoft.com under Email & Collaboration > Review > Quarantine.

Step 9: Repair Your Outlook Profile

A corrupted profile can cause Outlook to connect successfully but fail to download new mail.

1. Close Outlook.
2. Go to Control Panel > Mail (Microsoft Outlook) > Show Profiles.
3. Click Add and create a new profile with your account details.
4. Set it as the default and reopen Outlook.

If email starts arriving on the new profile, your old profile was the culprit.

New Outlook: Specific Checks

• Sign out and sign back in — your OAuth token may have expired.
• Check connected accounts — go to Settings > Accounts > Email accounts and ensure the account shows as connected, not errored.
• Sync frequency — new Outlook syncs on a schedule. Slow mail arrival is often a sync delay rather than a failure.

For related Outlook issues, see our guides on Outlook not syncing and Outlook search not working.

When to Escalate to Your IT Team or Hosting Provider

If you have worked through all the steps above and emails are still not arriving, the problem is most likely outside your local Outlook installation. Contact your IT team or email hosting provider if: senders are receiving non-delivery reports, your domain’s MX records have recently changed, your Microsoft 365 subscription is due for renewal, or the issue affects all users in your organisation rather than just your account. These are server-side or administrative issues that require access beyond what you can fix from within Outlook itself.

For a full index of every Outlook guide and troubleshooting fix on Serverman, see the Microsoft Outlook complete guide and troubleshooting hub.