MacOS Mail shows wrong amount of messages in an IMAP folder

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Level 1

9 points

MacOS Mail shows wrong amount of messages in an IMAP folder

I created a mail folder on my IMAP server using MacOS Mail, then moved all my messages of a certain year (say, 2022) into it. MacOS Mail shows there are 888 messages in that folder; other IMAP clients (Outlook, Thunderbird) show 938.

I create another folder and copy all messages into it, MacOS Mail says "Copying 938 messages...", then the new folder again shows 888, and other clients show 938.

I select Mailbox->Rebuild from the menu, the app says "Downloading 938 messages...", then again shows 888.

Same problem (different quantities) with almost every folder I create. I could easily demonstrate.

MacOS 26.0.1, MacBook Pro M1 16"

MacBook Pro 16″, macOS 26.0

Posted on Oct 30, 2025 2:40 PM

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Answer 1

Gennady M Author

Level 1

9 points

Nov 19, 2025 1:43 PM in response to AlWeir

I could do it (probably) on the server itself, but my question was wider: how can I trust Mail at showing email quantities at all, if it is obviously showing the wrong number?

I thought maybe I don't understand something or don't know something: perhaps it is counting related emails as one or it somehow does not could certain types of emails, otherwise why it is showing a smaller number than other email clients and when it is copying it, it shows a larger number, equal to what other client show, and then again the smaller number.

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Answer 2

AlWeir

Level 5

4,862 points

Nov 1, 2025 5:32 PM in response to Gennady M

I probably would have done that on the IMAP server rather than trust Mail to do it. Can you undo it without loosing any emails?

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