A few days ago, I decided to move nearly 80,000 messages from an IMAP server to a Gmail server using Mail.app on Sierra 10.12.1:Mail.app Activity window showing two tasks: "Moving Messages, 4 of 79,718", "Checking for Mail…"

This task still hasn't completed.

"Checking for Mail…" comes and goes as one might expect, and normal mail functionality seems to work fine. Connection Doctor shows nothing strange.

However, this task has been going on for days, and moves very slowly—I've left the computer on all night and it only chews through a few thousand, occasionally stopping with an error. If I restart Mail.app (it takes a bit to quit), it eventually comes back up with the same 79,718 messages needing to be moved.

Is there any way to terminate this process? I'm inclined to try another tool at this point, but I'd like Mail.app to stop trying to move these messages.

  • I'm seeing this on an Exchange account too. It looks to me like I was impatient and scheduled the same messages to be moved multiple times when it looked like the first move hadn't succeeded, and now it's stuck because it can't move a message which is no longer there.
    – tripleee
    Commented Nov 18, 2019 at 13:40
  • I'm having a similar problem with moving the IMAP messages to an iCloud server. I swear you could just cancel this process in previous Mac OS's with an X in that Activity Window next to the process. I see Mail processes in the Apple supplies Activity Monitor app, but I have no idea which one, if any, would cancel this annoying issue.
    – user376503
    Commented May 21, 2020 at 16:53

6 Answers 6


Two things which come to mind that you could try are:

  • pressing the Command + . keys
  • pressing the ESC key

Either way you may need to do this a few times and wait for the task to register what you're doing.

  • 3
    Both of those close the activity window immediately, but don't actually terminate the activity, unfortunately.
    – Mattie
    Commented Nov 18, 2016 at 21:30

Delete the account that you were moving mail to and it will cancel the move.

  • 1
    This is pretty drastic, and doesn't really work when the botched move is within your primary and single account, does it?
    – tripleee
    Commented Nov 18, 2019 at 13:36

The problem is likely Gmail. It's not well known, but Gmail throttles paid and free accounts once they move a certain amt of mail in the day. The last time I checked, it was 500 MB of mail -- and then you were throttled for 24 hours.

Maybe things have changed -- but this has been my experience in the past. Want to test it? Disable the Gmail account, and see if the other accounts download more quickly.


For me, quitting Mail seemed to cancel the stuck move.

Attempting to move the same messages again seems to get stuck once more but I'm guessing it's just taking a long time because there are several thousand.


I have a similar problem having accidentally moved / copied an archive folder of ~65,000 mails to a public folder on my employers mail server ...

After having spent all day copying mails, it is now in a near-endless loop showing a server error message for each further mail that it cannot be copied because the "quota" is exceeded.

Force-quitting and restarting Mail (with/without SHIFT key held) does not help as the process simply starts from the beginning again after a few seconds.

Restarting the computer does not help.

Deactivating Mail-Sync for that account does not help.

The side effect is that I am unable to use Apple Mail for ANY of the several accounts on the machine (MBP).

My only workaround is to use other clients / web-based mail clients

The only solution may be the suggested one to delete the mail account. :(

  1. quite Mail.app and open the Library/Mail folder. I then opened the V10folder (may change with your version) folder and MailData, see the screenshot,
  2. remove all files starting with Envelope Index in the MailData folder
  3. restart Mail.app - it should rebuild all indexes


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