How to fix Mac Mail app not syncing or receiving new emails

Summary

This guide helps you troubleshoot and resolve: How to fix Mac Mail app not syncing or receiving new emails. Follow the steps below to fix the issue.

Common Causes

When Apple Mail stops syncing or fails to receive new messages, it can disrupt your workday significantly. Sync issues in the Mac Mail app are often caused by corrupted mailbox caches, outdated connection settings, or conflicts with third-party security software. This guide walks you through a series of troubleshooting steps to get your email flowing again.

Quick Fix Steps

Before diving into detailed troubleshooting, try these initial steps to resolve the most common sync issues.

Restart the Mail App and Your Mac

1. Completely quit the Mail app by pressing Command + Q.
2. Restart your Mac by clicking the Apple menu  in the top-left corner and selecting Restart.
3. Open Mail again and check if new emails are downloading.

Check Apple's System Status

Before troubleshooting further, visit Apple's System Status page and confirm there are no outages affecting iCloud Mail or related services. If there is an outage, you will need to wait for Apple to resolve it.

Check Your Internet Connection

Ensure your Mac has an active internet connection. Try loading a webpage in Safari to confirm. If you are on a corporate or public network, certain ports may be blocked, preventing Mail from syncing.

Take All Accounts Online

1. Open the Mail app.
2. Click the Mailbox menu in the top menu bar.
3. Select Take All Accounts Online.

Detailed Instructions

If the quick fixes did not resolve the issue, follow these detailed steps to analyse and repair your Mail app.

Rebuild Your Mailbox

Rebuilding a mailbox forces the Mail app to re-download all messages and clear out corrupted data. This is the most effective fix for sync issues.

1. Open the Mail app.
2. In the left sidebar, select the mailbox or account that is not syncing.
3. Click Mailbox in the top menu bar.
4. Select Rebuild.

Verify Connection Settings

Incorrect incoming or outgoing server settings will prevent Mail from syncing properly.

1. Open the Mail app.
2. Click Mail in the top menu bar and select Settings (or Preferences on older macOS versions).
3. Click the Accounts tab.
4. Select the affected account from the list on the left.
5. Review the Account Information and Server Settings tabs to ensure the incoming and outgoing server addresses are correct.

Clear Cached Mail Data

Sometimes the Mail app's cache becomes corrupted and prevents new emails from displaying. Clearing the cache forces the app to fetch fresh data.

1. Quit the Mail app by pressing Command + Q.
2. Open Finder.
3. Press Command + Shift + G to open the "Go to Folder" window.
4. Paste the following path and press Go: ~/Library/Mail/V10 (substitute V9 or V8 if your macOS version uses an older folder).
5. Inside this folder, locate the files named Envelope Index, Envelope Index-shm, and Envelope Index-wal.
6. Move only these three files to the Trash. Do not delete or move any other files or folders.
7. Empty the Trash.
8. Reopen the Mail app. It will take some time to re-download your messages.

Troubleshooting

Check for macOS and Mail Updates

Outdated software can cause compatibility issues with mail servers.

1. Click the Apple menu  and select System Settings (or System Preferences on older macOS versions).
2. Click General, then Software Update.
3. Install any available updates for macOS.

Disable Antivirus or Firewall Interference

Third-party antivirus software or strict firewall settings can block the ports Apple Mail uses to communicate with servers.

• Temporarily disable any third-party antivirus software and check if Mail syncs.
• If you are using a VPN, disconnect it and test Mail again.
• Check your Mac's firewall settings under System Settings > Privacy & Security > Firewall (or System Preferences > Security & Privacy > Firewall on older macOS versions) to ensure Mail is allowed to receive incoming connections.

Remove and Re-add the Account

If none of the above steps work, removing and re-adding the account can resolve deep-rooted configuration issues.

1. Open the Mail app.
2. Click Mail in the top menu bar and select Settings.
3. Go to the Accounts tab and select the problematic account.
4. Click the – (minus) button at the bottom of the list to remove the account.
5. Confirm the removal.
6. Click the + (plus) button to add the account back and follow the prompts to enter your credentials and server settings.

Still Having Issues?