mail crash - OS 27.0

If Mail crashes every time you try to open it after updating to macOS 27.0, first restart your Mac and check Apple menu  >> System Settings >> General >> Software Update for any available update. 

Apple recommends restarting and updating macOS when an app unexpectedly quits or will not open. Apple Support: If an app on your Mac stops responding, closes unexpectedly, or won't open

If Mail still crashes, hold Shift while opening Mail. 

Apple states that this prevents Mail from restoring windows that were open when it was last quit. 

If that does not help, start the Mac in Safe Mode and try opening Mail again. Apple Support: Prevent apps and windows from reopening on Mac

If Mail still will not , testing it from a different macOS user account can help determine whether the problem is specific to the original user account. 

I would not remove the mail account or delete Mail's stored data at this stage.

Mailbox >> Rebuild can be left for later because Apple documents it for mailbox problems such as missing or garbled messages; it requires Mail to be open. Apple Support: Create or delete mailboxes in Mail on Mac

If Mail continues to crash, the Mail crash report is the next useful diagnostic information.

Examining it before making changes to Mail's accounts or stored data is preferable to assuming what is causing the crash.

If you have added an Exchange account to Mail, that might be causing it.

Go to System Settings > Internetaccounts and look up the Exchange account.

Use the switch to disable the account in Mail.

Open Mail and see if it works again.

If it does, you have the same issue as I have.

With Mail open, it's ok to enable the Exchange account again and it will reappear in Mail.

But as soon as you start the fetch new mails, it will crash again. Or when you close Mail and reopen it.

So many layers to the onion, but after a bit of searching I found this ( https://www.google.com/search?client=safari&rls=en&q=deleting+icloudmailsettings_macos.bundle&ie=UTF-8&oe=UTF-8 ) and 'for me' it worked.

After previously deleting every preference I could find Mail would not open with a "Welcome to Mail" prompt but rather straight into a user session which crashed out after 2-3 seconds. This time after following the advice in the above link it started with a "Welcome to Mail" followed by the usual iCloud login and 15 mins of download and syncing. So ( cautiously ) this worked ( for me ) and whilst I've lost all my smart mail boxes I know from experience that smart mail box V2 will be better than V1 when completed. Hope it helps !

I noted which items I used from the Exchange account and then removed it. Restarted the Mac to be sure.

Then I added the Exchange account back and for me it's working again.

Yes, that's exactly right, thank you. When I disabled the exchange account, Mail opened. Then I could re-enable the exchange account. But when I fetched new emails, Mail crashed.

Does Apple monitor these chats? Apple, do you know about this issue and can you please fix it? I believe this is an issue with OS 27.0.1 because I didn't have an issue until I upgraded to that version.

Have Mac Studio ( M1 Max ) recently upgraded to OS 27.0. After a few days of normal operation Apple Mail now quits after 2-3 seconds. I have followed Owl-53s recommendations ( thank you ) but either the apple.com.mail.plist file is either locked or not present. Also, a Library folder appears to be present at more than one location depending on the 'level' one accesses which is confusing. Those relevant files I have found and managed to delete have not solved the problem.

Mail is crashing every time I try to open it after I upgraded to OS 27.0.1 I tried restarting, and I tried holding shift while opening Mail. I cannot get it working so I have switched to Outlook. Any suggestions?

To be sure I understand, this time you removed the account entirely rather than disabling it. Then you restarted the Mac and added it back.

What do you mean when you say you "noted which items [you] used from the Exchange account"?

Update: starting in safe mode did not fix the problem. I think this is a problem with 27.0.1.

Pretty sure I deleted all mail system files & folders ( and all messages ), reinstalled OS27 . . . no change even from a ’virgin’ start . . . window opens for 2-3 seconds then crashes ☹️

Correct. And the items to note are what you use from the account: mail, calendar, contacts etc.

Dear bestaatdezeal, your uninstall/install technique worked for me--thank you so much. I appreciate this community!