What to do when Apple Mail is not working

5 min read

Are you here because Apple Mail is not working correctly? If it keeps crashing, stalling, not even loading, or quitting unexpectedly, you've come to the right place.

Thankfully, we've got some quick tips that will help if:

  • Mac Mail keeps crashing once it's been open for a while.

  • Apple Mail keeps quitting unexpectedly.

  • Mac Mail won't open.

How to troubleshoot Mail problems on Mac

The next couple of tips will require you to follow them in this exact order and test after each step. Let’s jump right in.

1. Restart your Mail app and your Mac

The very first thing to do is to restart your Mail app. To do it, press Option-Command-Esc to open the force-quit menu. Select Mail to quit the app. Then, reopen the app and see if the issues disappeared. 

Restart Mail app

If restarting your Mail app hasn't helped, it's time to restart your Mac: go to the Apple Menu on the top left and select Restart. See if that worked and move on if required.

Restart your Mac

2. Rebuild Mail

Don't worry; this isn't as daunting as it sounds. Rebuilding your mailboxes might completely solve the problem.

Here is how to rebuild your Mac Mail:

  • Open your Mail app.
  • Select a mailbox from the left sidebar.
  • On the top menu, select Mailbox > Rebuild.

Rebuild your Mail

Try this for all your Mailboxes, then close Mail and reopen it. Now, test again.

3. Reset Mail app

Use CleanMyMac X to quickly and securely reset Mac Mail. It won't delete the program; instead, it brings it back to its default state. Here's how:

  1. Open the app and select Uninstaller from the left sidebar (free download here).
  2. Choose the Mail app in the list.
  3. Click the little arrows next to Uninstall to reveal the Reset button. 
  4. Finally, click Reset.

Safari reset selected in the Uninstaller module in CMMX

4. Update your macOS

Keeping your Mac up to date is a sure way of working out the kinks. It's obvious but worth a try. How to check if you have the latest update installed:

  1. Select the Apple menu top left and select About This Mac > More Info.
  2. Select Software Update to find out if you need a quick update.
  3. If there are any updates available, click Upgrade Now and follow the on-screen instructions.

System Preferences - Software Update

Test again, and if Mail is still not opening on your Mac, it's time to move to the next tip.

Tip: Mac Mail app not working is just one issue you can experience while using your Mac. Check out other blog articles to learn how to fix Apple mouse not working, Trackpad glitches, and other nasty Mac problems.

5. Disable your email accounts

If you have multiple accounts, it's worth disabling them and then reloading them one by one to try and find if an account is corrupt. How to manually disable your Mail accounts:

  1. Open the Apple Menu > System Settings.
  2. Select Internet Accounts.
  3. From the list, select your mailboxes, click on them, and hit Turn Off in iCloud Mail.
  4. When you have disabled all Mail accounts, reload Mail and check if it worked.

Disabling mail account

If the Mail app now works, then one of your Mail accounts is causing the issue. To find out which one, turn your accounts back on one by one, following the steps above to find the offender. Once found, delete the mailbox account altogether by clicking the Delete Account button and reinstalling the mailbox.

6. Remove problematic Mail attachments

Sometimes, when Mail is not working on a Mac, it can be caused by a dodgy mail attachment. This can be hard to identify unless Mail immediately crashes when you click on a specific email. 

If your inbox contains a mountain of messages like mine, it can be tricky to pinpoint the corrupt item. It's a lot easier to clean up your attachments with a tool like CleanMyMac X. Its dedicated Mail Attachments module can quickly and safely remove local copies of email attachments and downloads, clearing space and eliminating app crashes. Bonus point, Apple notarized the app, so it’s safe for your Mac.

How to remove mail attachments with CleanMyMac X:

  1. Open the app — download the free version here.
  2. Select Mail Attachments from the left sidebar and click Scan.
  3. Wait for the Scan to finish, then select which mailboxes to clean and click Remove.

CleanMyMac X - Mail Attachments module

You know the drill — test your Mail and move on if needed. 

7. Remove and reindex envelope files

Mail uses an envelope index to catalog and search message headers; these can become defective and cause Apple Mail not to work.

How to manually remove envelope files:

  1. Quit Mail and open the Finder.
  2. Holding down the Option key from the top menu, select Go > Library.
  3. Now, select Mail > V9 folder (depending on your macOS, this could be another number).
  4. Now, select the MailData and locate the following files:
    Envelope Index-shm
    Envelope Index-wal
    Envelope Index
  5. Copy and paste them on your desktop, deleting the original files in MailData. Then reopen Mail and test.

    Reindex envelope files

    If it's working, delete the files on your desktop. 

    Don't fancy poking around in your Library folder? There's a quicker way to do this with the app I mentioned earlier. CleanMyMac X has the Maintenance module that can do this for you in just a few clicks.

    How to remove and reindex envelope files the quick way:

    1. Open CleanMyMac X.
    2. Select Maintenance from the left sidebar and then select Speed Up Mail.
    3. Click Run and wait for the task to complete.

    Speed up mail with CleanMyMac X


    8. Test Mail in safe mode

    Safe mode helps to identify whether an issue is being caused by startup software. It also clears the cache and repairs disks — sometimes solving what’s wrong with Mail altogether.

    To start Macs with Apple silicon in safe mode:
    1. Shut your Mac down and wait 10 seconds. 

    2. Turn your Mac back on, pressing and holding the power button for 10 seconds.

    3. When the startup window appears, release the power button.

    4. Now, select your startup disk, then press and hold the Shift key.

    5. Click Continue in Safe Mode and release the Shift key.

    Boot your Mac into safe mode

    To start Intel-based Macs in safe mode:
    1. Shut down your Mac and wait 10 seconds.

    2. Restart your Mac and press and hold the Shift key on startup.

    3. When the login window appears, it's time to release the Shift key.

    4. You might need to log in again. But you will see "Safe Boot” on either the first or second login window in the top right-hand corner.

    Boot your Mac into safe mode

    Now, open the Mail in safe mode and see if it’s working correctly. If the issue is no longer disturbing you, the problem should have been resolved. Now restart your Mac as usual. 

    These troubleshooting tips should fix Mail if it’s not working correctly on your Mac. Time to get back to those emails. 

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