Mail Not Responding after Sequoia 15.4 upgrade

Yup, Mail won't launch. Hangs and has to be force quit. Repaired permissions, used a utility to optimize Mail, re-installed the OS, Mail still won't launch, hangs and has to be force quit.

Not good.

WORK AROUND & FIX:

You need to change the 'Check spelling' feature.

If, 'Check Spelling: When I Click Send' is currently selected.

You need to change it to either 'As I Type' or 'Never'.

Go To: Mail > Settings > Composing > Check spelling: [change to one of the above]

Confirm one of these new settings are selected, Exit Settings and you'll be good to go.

Apple have confirmed today 8th April 2025 it is a known issue that when sending an email with Spell Check selected as 'When I Click Send' Apple Mail freezes.

Please pass this workaround and fix on to others in other Chats. This issue, since the Sequoia 15.4 [24E248] Upgrade has been driving me nuts!! All good now 👍🏻

Had same problem. After upgrading to Sequoia 15.4, Mac Mail "Send" button on email message grayed out and email would not send. Changed "Check Spelling" to "Never." Emails now seem to be sending properly. Thank you fletcher135.

I did two things, not sure which worked, maybe both...

1. I deleted a few unused pop mail account I hadn't used for years, and was just ignoring,
2. I turned off categories on the one account it was active in.

Thanks for the suggestions on pop mail accounts and categories.

It's working now.

To get the mail app to launch, i made all my email accounts inactive and opened the app. Then in settings/accounts turned on the email accounts one by one. I think it has something to do with POP emails.

POSSIBLE WORK-AROUND FIX - If you are able to open Mail and compose, but the send button grays out when you hit it - it looks like this is a spell-check issue. I hit send, the button grays out, I then go to "Edit / Spelling and Grammar" and click "Check Document Now", then it sends. Hope this helps some people.

Kind of hard to believe they'd let Sequoia 15.4 out the door with none of the alpha testers catching the fact that Apple Mail's spell-check kills the ability to SEND. I only used spell-check for one reason - gives me one last chance to make sure a) i'm emailing the right person, b) i'm saying what i meant to say, c) if there's a more economical way to say it, etc. Helpful - but Apple came up with the ultimate check on whether the email is correctly addressed and written — just not be able to send it at all.

I have the same issue since "upgrading" to Sequoia 15.4.1. Mail opens and hangs, application not responding. Force restart just leads to the same thing. Deactivating all mail accounts in Settings->Internet Accounts will allow for Mail to open, but as soon as I enable one account, Mail hangs again. Tried removing ~/Libary/Mail and let Mail recreate, but it still hangs. Apple needs to fix this, Mail is completely broken post Sequoia 15.4.1. Very frustrating.

I'm also experiencing Mac Mail issues using MacBook Pro 14 (M3) after updating to Sequoia 15.4. Except I'm using Bell Sympatico email and do receive emails but can't reply or send new outgoing emails. I deleted my email account in Mac Mail and then restarted the MBP and then added the same Bell sympatico email account, and then restarted, but this did not solve the problem. Curiously when I updated my Mac Studio (M4) to Sequoia 15.4 and my email didn't work, after I deleted my email account and added it back again as I indicated above, the email works.

Same issue. Cannot send and after discovering that the Server settings were all kiboshed after the Sequoia update, and having re-entered them, my Gmail account says nope- your password is incorrect. Grrr.

I too have been having the issue of mail not sending after the upgrade to 15.4

I can type an email and hit send and maybe it would send.. most often not.. I logged into my iCloud account on line and had no issues..

The I read a note on a community site.. that if after writing the email.. and you hot send.. and it doesnt send.. the send button only turns gray.. that if you edit a word in the body of the email.. it would then send..

And so far today.. that is what is happening. I will add random letters at the bottom of the email.. hit send.. and then delete those letters and it goes

Silly, I know.. and is a glitch that Apple will need to address

The way I've been able to get Mac Mail back to working is to delete my email account twice with a restart in between. Delete Mac Mail email account > restart > add email account to Mac Mail > then delete Mac Mail email account > restart. This finally worked.

I have the same issue. When starting the mail, it will crush immediately.

On another computer I have still 15.3. There, the email first crushed, too, but after restart it works. Seems to have something to do with 15.4.

This needs an urgent fix!!!

Good Lord - what a mess! I have 4 emails in my MacMail - 1 Microsoft, and 3 Gmail - Of all times for Microsoft to actually work! I had to sign back into all the Gmails, restart, restart, restart, restart, Check Spelling, Categories, etc... not sure which trick finally worked, but I got things up and going in an hour or so.