Mail Quit Unexpectedly

Update

Update your Mac. Then try to open Mail again. When you update the macOS software on your Mac, Mail will also be updated. And this may resolve your problem. Here is how:

• If you are using macOS Mojave or later: Go to System Preferences and Software Update.
• If you are using macOS High Sierra or earlier: Open the App Store and click Updates.

Rebuild

Try rebuilding your mailboxes to see if this fixes your problem Here is how:

• Open Mail.
• Select a mailbox.
• Click Mailbox > Rebuild.

You may not be able to rebuild since Mail keep crashing. But try this if you can.

Isolate the problem

Following the steps below will help you find the problematic mail account. Here is how:

• On your Mac, go to System Preferences and Internet Accounts.
• Disable all email accounts by unchecking the Mail option.
• Now all of your Mail accounts are disabled, try to open Mail. Does the app crash or not?
• If it opens without crashing, this means that one of your accounts are causing this problem. What you can do is to turn each account on one by one and test Mail after turning on each account. Repeat this until you find the account that is causing this. And when you find the problematic account, what you can do is to delete the account and then re-add.
• If Mail crashes, turn on all of your accounts and go to the next step below.

See if you can start Mail in Safe Mode

Safe Mode (also called Safe Boot) may fix your problem. Safe Mode clears caches and repairs disks. Here is how:

• Turn off your Mac.
• Turn on your Mac and immediately press and hold the Shift key.
• Keep holding the Shift key until you see the login screen.
• Login.
• When your Mac finishes starting up, now try to open the Mail app. Does it crash or not?
• Restart your Mac again. This time restart normally. Do not press any keys. This will exit Safe Mode.
• Again test Mail.

Delete preference files

If the Mail preference files are corrupted for some reasons, this may cause crashes. Please note that when you remove these files, your account settings and preferences will be gone. Here is how:

• Quit Mail.
• Go to your desktop and press and hold the Option key.
• In the Finder, while holding the Option key, click Go and then Library.
• Open the Preferences folder.
• Locate these two files: com.apple.mail.plist and com.apple.mail-shared.plist
• Move these files to the Trash.
• Restart your Mac.
• Then try to open Mail to see if it works.