Using Yosemite (OSX 10.10) and the included Mail application (which describes itself as "Version 8.0 (1990.1)" to read mail held on a company Exchange server, I am finding that the unread marks for messages are not being reliably updated. Before the Yosemite upgrade, whenever I selected the message summary in the left hand pane, it was instantly marked as "read". This no longer happens reliably: some messages are marked as read, others are not. For example, in this screenshot, I have clicked on all of these messages, and some have updated and some have not:

screenshot showing mix of read and unread

I have also noticed that the unread count on the Inbox does not behave consistently: sometimes it is decremented even though the message still shows as Unread, sometimes the number does not change.

In case it matters, I'm running on an Early 2011 MBP with 8Gb RAM.

This seems to be only an issue with the Exchange account. I have two other mail accounts in Mail, and have no issues with either of them. I've looked at the settings for my Exchange account, and can't see anything that seems unusual.

Has anyone else experienced this and resolved the problem?

  • While they mention GMail, I wouldn't be surprised if this update (currently in testing) fixes it: 9to5mac.com/2013/10/31/… -- And yes, I'm having exactly the same problem.
    – salgiza
    Commented Oct 27, 2014 at 12:48
  • According to the screen shot on 9to5mac.com, one of the three areas of focus of the first beta of the first Yosemite upgrade is "Exchange accounts in Mail". So there's hope. Commented Nov 7, 2014 at 0:59

6 Answers 6


Same issue, and on two different machines. One is a MBP (mid 2010) the other is an iMac (early 2013). I am getting mail from an Exchange server. I find that closing and reopening mail will temporarily solve the problem. I also find that switching mailboxes and switching back works.

  • Yes, I've found that just switching to one of my other inboxes and back forces the display to update, but it's still a real annoyance. Commented Oct 22, 2014 at 21:04

Had the same issue, and for me it helped rebuilding the inbox.

Select the Inbox then go to the Mailbox menu and then select Rebuild in the bottom of the menu.

If the option Rebuild are disabled, make sure you are in Mailbox view so you can have the folder selected. To get the Mailbox view click Mailboxes in the Favorites bar, or choose View > Show Mailbox List

The inbox might go blank/white for a while when mail.app are rebuilding its indexes. It will fetch all the emails from the server again so it might take some time for large mailboxes.


I am having this problem when pulling mail in from a Gmail account. It was not happening yesterday, but is happening today.

If I quit and restart Mail, the read messages are updated.


As mentioned here as well, you could try to set the following in your Terminal:

defaults write com.apple.Mail MarkAsReadDelay 0
  • This seems unlikely to be the problem, since the issue is only with the Exchange account. I tried it anyway, and - sure enough - didn't notice any change. Commented Nov 12, 2014 at 1:54

The Yosemite update appears to have fixed the problem. Now running OS X 10.10.1, with Mail version 8.1, the unread marks are updating instantly.

UPDATE: I was too optimistic. It's better than it was, but there are still messages marked as unread that I have read.

UPDATE 2: After running with the second Yosemite update (version 10.10.2) for a week, which includes Mail version 8.2, it actually appears to be fixed. Yay.

  • 1
    I am on 10.10.2, and there has been no improvement. Commented Mar 5, 2015 at 11:50

Same issue on a brand new Macbook Pro, on two different accounts, one Exchange and one GMail/IMAP.

After a restart the flags are correct. Approximately half of the messages I receive are affected.

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