Mail Not Responding after Sequoia 15.4 upgrade

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 👍🏻

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.

I had this problem: after upgrading to Sequoia 15.4.1, my Mail application would not open. It just said "Application Not Responding". I went into Settings / Internet Accounts and deleted a whole lot of inactive POP accounts, and then Mail opened normally.

I did notice that in the list of Internet Accounts, my two active POP accounts appeared twice, once marked Active and once marked Inactive. So it's possible that there's a bug in there somewhere.

Thanks to this forum for that workaround. Pretty significant bug for Apple to be "aware of" and not fix.

I had Spell-check set for "When I Click Send" - not for the annoying, counterintuitive spell-check, but to have something, anything, give pause: am I sending this to the right person? did i need to explain the rotation of the earth to say it's a nice day? was I cranky and descended unecessarily into the evil domain of Snarkland? To try and slow my roll, I even removed the paper airplane SEND icon from the toolbar - using the menu slows me down sometimes. But due to this bug I've had to let go of spell-check delay. For now, I rely on a long email unsend delay. Works ok, but if you go to other tasks in mail, and hit the Undo button (for instance, editing text) - Apple takes the email out of the queue and unsends it, so you go about your day not knowing it was never received because it was never sent at all.

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.

WORKING WORKAROUND - NO PERMANENT FIX:

Try checking the "Open with Rosetta" option in the app finder info.

It did the trick for me.

It's a workaround, that does not address the root cause of why Mail.app stops launching...

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.

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.

Your solution worked, deleting some of the accounts resolved the problem

Thanks for sharing

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.

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.

I read from another forum that you should disable the category feature. It might be causing the issues with certain email accounts.

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