Mail: Occasionally messages will not send, but will go to Drafts instead

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Mail: Occasionally messages will not send, but will go to Drafts instead

From time to time, when I send emails (using the built-in Mail app on my MacBook Pro), the message will appear to send, but will not actually send. I can find it later in Drafts, but not in the Sent messages, and the recipients do not receive the message.

I have multiple email accounts, some using Gmail and some using my own email host. When the problem occurs, it occurs across all these accounts. If I restart Mail, I can go in and re-send the emails from Drafts, along with new emails, and they will actually send, at which time they are removed from the Drafts folder and appear in their appropriate Sent folders. Sometimes the problem reoccurs shortly thereafter and I have to restart Mail again.

It does not appear to be isolated to any particular recipients. This occurs with people I email occasionally as well as people I email multiple times a day. Once it starts, most if not all emails do not go out. Once it is fixed, all emails return to functioning properly.

It happens wether or not I'm using a VPN, and regardless of whether I'm on my home network or another network. Sometimes it seems that a change in one of these does trigger the issue, but I can't say for sure, and that is definitely not always the case.

I do use an extension in Mail (Mailbutler.io) for scheduling sends and tracking receipts. That is the only extension I have, and I've used it for many years.

This problem has been occurring on an occasional (seemingly random) basis for quite some time, but has happened 3 times in the last few months.

I'm on a MacBookPro, 16in 2023, running Ventura (13.7.4), and Mail 16.0.

MacBook Pro 16″

Posted on Jul 29, 2025 4:42 AM

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Answer 1

Aug 30, 2025 7:07 AM in response to Robin Darroch

Robin Darroch wrote:

So it's not just me! This describes exactly a problem that I've been having with mail from time to time over the past couple of years. It only happens occasionally - maybe once in 20 or 30 sent messages - and there doesn't seem to be any rule about when it does or doesn't happen: just yesterday I sent three emails to my accountant (all written as replies to the same email, each one with a couple of MB in attachments, and all three sent [or "sent"] within about 15 minutes of each other). The first and third messages actually sent, the second message I just noticed was still sitting in my drafts folder, unsent, and missing the last few words of the message I had typed before clicking "send".

I do not use Mailbutler, but I also have one extension installed (SpamSieve).

SpamSieve can work without its Mail extension, so you could try unchecking that in Mail’s settings and see whether you notice a difference. If not, the problem isn’t related to extensions. If so, maybe there’s a general Mail issue affecting all extensions, so please let us know (spamsieve@c-command.com) and we can make a bug report to Apple.

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Answer 2

Aug 29, 2025 9:33 PM in response to candez

So it's not just me! This describes exactly a problem that I've been having with mail from time to time over the past couple of years. It only happens occasionally - maybe once in 20 or 30 sent messages - and there doesn't seem to be any rule about when it does or doesn't happen: just yesterday I sent three emails to my accountant (all written as replies to the same email, each one with a couple of MB in attachments, and all three sent [or "sent"] within about 15 minutes of each other). The first and third messages actually sent, the second message I just noticed was still sitting in my drafts folder, unsent, and missing the last few words of the message I had typed before clicking "send".

I do not use Mailbutler, but I also have one extension installed (SpamSieve). I also have multiple email accounts including Gmail and my own hosting service.

I don't need to restart mail in order to send a message - as soon as I notice it's in the Drafts folder, I can open it, click "send", and it will go.

I wish I knew where to start with this - it's just so very random!

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Answer 3

Aug 30, 2025 6:19 PM in response to michaeltsai

OK - that's an interesting idea. I'm having trouble getting SpamSieve configured without the plug-in however. In the SpamSieve settings window, under Apple Mail, only the options "Disable spam filtering in Apple Mail" and "Enable spam filtering using Mail extension" are available - the "Enable spam filtering using Mail plugin" is greyed out. When I attempt to follow SpamSieve's instructions for enabling the mail plugin, I hit a dead end when it tells me to go into Mail and under Settings->General click the Manage Plug-ins... button ... because that button doesn't exist.

I would prefer not to just run without SpamSieve for as long as it will take for me to be confident this has changed the behaviour - as I mentioned, it's often weeks or longer at a time without observing this bug at all (I don't send a huge number of emails), so I'll probably need to go for at least a month before even being able to make an assumption one way or the other... and we'll only know for sure if it turns out the behaviour continues without the extension enabled.

My setup: Mail 16.0 on Sequoia 15.6.1, M1Max MBP.

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Answer 4

Aug 30, 2025 6:33 PM in response to Robin Darroch

Robin Darroch wrote:

When I attempt to follow SpamSieve's instructions for enabling the mail plugin, I hit a dead end when it tells me to go into Mail and under Settings->General click the Manage Plug-ins... button ... because that button doesn't exist.

You don’t want the plug-in. Apple removed support for Mail plug-ins a few years ago.

You want to select Enable spam filtering using Mail extension and Check inboxes for new messages not sent to Mail extension in SpamSieve’s Settings > Apple Mail > Setup and uncheck SpamSieve in Mail’s Settings > Extensions.

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Answer 5

Aug 30, 2025 11:20 PM in response to michaeltsai

Done - let's see how it goes!

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