How to Fix Apple Mail When It Gets Stuck

Apple Mail is a solid email client until it isn’t. The most common symptom is the dreaded “Copying message” indicator that spins forever in the Activity window, usually caused by a large attachment or corrupted message that Mail can’t process.

This guide covers the current versions of macOS (Ventura 13, Sonoma 14, and Sequoia 15) and includes troubleshooting steps for iPhone and iPad.

Quick fix: Remove the stuck message via webmail, then rebuild the mailbox in Mail.

Mac Troubleshooting Steps

1. Quit and Restart Mail

The simplest fix is often the right one:

• Quit Mail completely (Cmd+Q, not just close the window)
• Wait 10-15 seconds
• Reopen Mail

If it’s still stuck, restart your Mac and try again.

2. Take Accounts Offline, Then Back Online

Force Mail to reset its connection to the server:

• Mailbox menu > Online Status > Take All Accounts Offline
• Wait 30 seconds
• Bring All Accounts Online
• Watch Window > Activity to see if “Copying message” clears

Note: This is under the Mailbox menu, not the Mail menu.

3. Delete the Problematic Message from Webmail

Often the fastest solution:

• Sign into your email provider’s webmail (Gmail, Outlook, Fastmail, etc.)
• Sort by date or size to find the suspect message
• Check Inbox, Sent, Drafts, and Trash for large or recent messages
• Delete or move the problematic message
• Empty Trash on the server
• Reopen Mail and let it resync

4. Stop Downloading Large Attachments

Prevent Mail from choking on big files:

• Mail > Settings > Accounts > [Your Account]
• Under Account Information, set Download Attachments to “None” or “Recent”
• Let Mail sync
• Once stable, restore your preferred setting

5. Rebuild the Mailbox

Force a fresh index and resync:

• Select the problematic mailbox (usually Inbox)
• Mailbox menu > Rebuild

This can take time on large mailboxes but often fixes corrupted indexes.

6. Delete the Envelope Index Files

Clear Mail’s local database cache:

1. Quit Mail
2. Open Finder and navigate to ~/Library/Mail/V10/MailData/
3. Delete these files:
   • Envelope Index
   • Envelope Index-shm
   • Envelope Index-wal
4. Reopen Mail—it will rebuild the index

Note: Use V10 for Ventura and Sonoma. Sequoia may use V10 or V11.

To access the Library folder: Finder > Go menu > hold Option > Library.

7. Adjust Server-Stored Folder Settings (IMAP)

Sometimes server folders cause sync loops:

• Mail > Settings > Accounts > [Your Account] > Mailbox Behaviors
• Temporarily uncheck storing Drafts, Sent, and Junk on the server
• Let Mail settle
• Re-enable as needed

8. Use Connection Doctor

Check if your account can connect to the server:

• Window > Connection Doctor
• Green = good, Red = problem
• If red, update your password or re-authenticate (especially for OAuth accounts like Gmail)
• Verify server settings match your provider’s documentation

9. Remove and Re-Add the Account (Last Resort)

Nuclear option for persistent issues:

• Mail > Settings > Accounts > select account > click “−”
• For IMAP accounts, your mail stays on the server
• Add the account back with “+” and let Mail auto-configure

Warning: Don’t do this with POP accounts unless you have backups—POP downloads may be your only copy.

macOS-Specific Issues

Mail Privacy Protection (Monterey and Later)

If emails aren’t loading images or remote content:

• Mail > Settings > Privacy
• Try disabling “Protect Mail Activity” temporarily
• This feature can sometimes block legitimate content

Mail Extensions (Sonoma and Later)

Important: Traditional Mail plug-ins no longer work in Sonoma and Sequoia.

• Old plug-ins in ~/Library/Mail/Bundles/ can cause crashes
• Check Mail > Settings > Extensions for the new extension system
• Remove old plug-ins before upgrading to Sonoma

iCloud Private Relay Conflicts

If you use iCloud+ Private Relay and experience Mail issues:

• Private Relay outages can affect Mail Privacy Protection
• Some email providers have authentication issues with Private Relay IPs
• Try temporarily disabling: System Settings > Apple ID > iCloud > Private Relay

Sequoia-Specific Problems

Known issues after upgrading to macOS 15:

• “On My Mac” local folders may disappear—re-enable in preferences
• Folder sync problems between devices
• Email signatures not applying correctly

Recommendation: Backup ~/Library/Mail/ before upgrading to Sequoia.

Server-Side Causes

Check your email provider’s webmail for these issues:

iPhone and iPad Troubleshooting

Mobile Mail issues follow similar patterns:

1. Force-quit Mail and toggle Airplane Mode on/off
2. Restart the device
3. Settings > Mail > Accounts > select account > toggle Mail off, wait 30 seconds, toggle on
4. Delete the stuck message via webmail
5. Remove and re-add the account (IMAP only)

When to Contact Support

If you’ve tried everything:

• Email provider issues: Contact your email provider (Gmail, Outlook, Fastmail, etc.)
• Apple account issues: Apple Support
• Persistent crashes: Consider a clean macOS install as last resort

Official Apple Documentation

• Mail User Guide for Mac
• iPhone Mail Setup
• iPad Mail Setup