Mac Mail Problems on Big Sur? Fixes That Work
If you’re experiencing Mac Mail problems after upgrading to Big Sur, you’re not alone—common issues include mail not sending, crashing on launch, and accounts showing errors. This article explains the most frequent Big Sur Mail problems and provides step-by-step fixes you can try right now.
Why Big Sur Affects Mail
macOS Big Sur (11.x) introduced a major redesign of Mail, along with changes to how the system handles privacy, permissions, and background processes. These changes can cause older preferences or caches to become incompatible, leading to crashes, slow performance, or accounts that won’t sync. Additionally, Big Sur changed the default mail storage location and altered how Mail interacts with iCloud and third-party email providers.
Common Big Sur Mail Problems and Quick Fixes
Here are the most frequently reported issues and the first things to try:
- Mail crashes on launch – Restart your Mac, then open Mail while holding the Shift key to disable mail rules temporarily. If it opens, a rule is causing the crash.
- Mail won’t send or receive – Check your internet connection, then go to Mail > Preferences > Accounts and verify your server settings. Sometimes toggling the account off and on forces a refresh.
- Mail is slow or unresponsive – Rebuild the mailbox by selecting the mailbox in the sidebar, then choosing Mailbox > Rebuild.
- Search not working – Spotlight indexing may have failed. Go to System Preferences > Spotlight > Privacy, add your Macintosh HD, wait a moment, then remove it to re-index.
- Emails appear blank or missing – This is often a cache issue. Quit Mail, then in Finder press Cmd+Shift+G and go to
~/Library/Containers/com.apple.mail/Data/Library/Caches. Delete the contents of that folder, then reopen Mail.
Step-by-Step: Fix Mail Crashing on Launch
If Mail crashes immediately when you open it, follow these steps in order:
- Restart your Mac to clear temporary glitches.
- Open Mail while holding Shift to disable rules. If it opens, go to Mail > Preferences > Rules and delete or disable any recent rules.
- If it still crashes, reset Mail’s preferences: quit Mail, then in Finder go to
~/Library/Preferencesand movecom.apple.mail.plistto your Desktop. Reopen Mail—you’ll need to re-enter account settings. - If the problem persists, check for a corrupted mailbox. In Mail, select the problematic mailbox and choose Mailbox > Rebuild.
- As a last resort, delete the Mail app’s container folder: quit Mail, then delete
~/Library/Containers/com.apple.mail. This resets Mail entirely—you’ll lose local drafts and cached emails, but your server copies remain.
How to Fix Mail Not Sending or Receiving
When Mail can’t send or receive, the issue is usually with account settings or a temporary server problem.
- Check your internet connection by opening a website in Safari.
- Go to Mail > Preferences > Accounts, select your account, and verify the incoming and outgoing server settings with your email provider’s documentation.
- If you use iCloud, ensure you’re signed in to iCloud in System Preferences and that Mail is enabled in iCloud settings.
- For Gmail or Yahoo, you may need to generate an app-specific password if you use two-factor authentication.
- Toggle the account off and on: In Preferences > Accounts, uncheck the “Enable this account” box, wait a few seconds, then recheck it.
When to Rebuild or Reset Mail
Rebuilding a mailbox is a safe first step for many issues—it re-downloads and re-indexes messages, fixing corruption without losing data. To rebuild, select the mailbox in the sidebar and go to Mailbox > Rebuild. This can take a while for large mailboxes. If rebuilding doesn’t help, you may need to reset Mail entirely by deleting the container folder as described above. Only do this if you have backups of important local emails, because it removes all locally stored messages and drafts (though server copies remain).
Alternatives to the Built-in Mail App
If you’ve tried all the fixes and Mail still misbehaves, you might consider a third-party email client. Popular options include Microsoft Outlook, Spark, Airmail, and Thunderbird. These apps often have more robust search and better handling of large attachments. However, they may require a subscription or in-app purchases. Before switching, test one with a free trial to see if it meets your needs.
Frequently Asked Questions
Why does Mail crash only after updating to Big Sur?
Big Sur changed how Mail stores data and handles permissions. Old caches and preferences can become incompatible, causing crashes. The fixes above address these by resetting caches or preferences.
Will I lose my emails if I delete the Mail container folder?
No, your emails are stored on your email server (e.g., iCloud, Gmail). Deleting the container only removes local copies and settings. After re-adding your account, Mail will re-download messages from the server.
How do I re-index Spotlight for Mail search?
Go to System Preferences > Spotlight > Privacy, add your Macintosh HD to the list, wait a moment, then remove it. Spotlight will re-index your entire drive, which can take a few hours. After that, Mail search should work.
Can I downgrade from Big Sur to fix Mail?
Yes, you can reinstall an older macOS version, but it requires erasing your disk and restoring from a backup. It’s a drastic step—try all other fixes first. Also, check if your Mac supports the older macOS version.
Why does my Gmail account keep asking for a password in Big Sur?
If you have two-factor authentication enabled, Gmail requires an app-specific password for third-party apps. Go to your Google account settings, generate an app password, and use that in Mail instead of your regular password.
Is there a way to prevent these problems in the future?
Keep your Mac updated to the latest version of Big Sur (or newer macOS), and regularly rebuild mailboxes if you notice slowdowns. Also, ensure your email provider’s settings are up to date, as they occasionally change server addresses.
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