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Apple Mail new mail/reply windows always open on different display

Hey All, Curious if anyone has seen this...


I have a 2013 iMac at home, with 2 external displays. I use Apple mail, which I keep open on the "right" side display.

For reasons that I have not been able to figure out, whenever I create a new message or reply to an existing message, the message window opens on the opposite monitor, in this case the "left" side, at the extreme left side of the left monitor.


If I switch the Apple Mail main window to the left display, the new message window opens on the right side display.

Switching the ports that the displays are connected to doesn't change anything.

This issue does not occur with only 1 or 2 displays; only with 3 displays total.


This has been happening for some time, since High Sierra (currently on Catalina), and only happens with Mail. No other apps have this issue.

I recently swapped out the HDD/SSD combo for a singled 2 TB SSD, so I started with a clean drive, installed Catalina, and transferred the home folder over using Migration assistant. The behavior did not change.



My assumption is that this a cache file, or plist, or something in the home folder, but its definitely not a file directly related to Apple Mail. I've rebuilt Mail multiple times, never importing previous settings (only previous mail messages).


Any thoughts?


TIA






iMac 27", macOS 10.15

Posted on Apr 23, 2020 10:26 AM

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Question marked as Top-ranking reply

Posted on Apr 23, 2020 3:21 PM

Last window position is normally stored in the app's preference file, ~/Library/Preferences/ for un-sandboxed apps, and ~/Library/Containers/<app container>/Data/Library/Preferences/.


The app container is named in revers domain convention, e.g., com.apple.mail

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8 replies

Apr 23, 2020 12:33 PM in response to Barney-15E

I don't experience this issue with 2 displays. I recently (just as I was starting my work from home due to COVID-19) had to replace a monitor due to failure, so for a short while was down to 2 monitors.

No issues.

Add on a new 3rd display, problem comes right back.


  • What desktop and display do you have Mail assigned to when you have three monitors?

Are you referring to Mission Control- Not using it. All displays are contained in a single expanded desktop.

The main Mail viewer window is always on the right side of the desktop (right side display, a Dell Ultrasharp 27")

If I select a message and then Cmd-N or Cmd-R (or Cmd-Shift-R), a message window opens on the far left side of the left display (LG 34" ultra wide- the new one)

From within Mail I can click on the Window menu and select Move to iMac or Move to Dell, which works just fine, but its not sticking. The next message I open or reply to goes right back to the LG, even after a quit and relaunch or a restart.


Thats why I was thinking this might be related to a persistent file in ~/Library, but so far I have found nothing obvious. Mind you, I'm only searching based on file name and location, not file content, but there is nothing in the ~/Library/Mail folder, so I was thinking of something that maintains last known windows location (like the Finder trick you asked about earlier). And that would make sense given this has been persistent over several OS versions, and a wipe/clean install/home folder migration.

Apr 24, 2020 9:03 AM in response to Barney-15E

So, I found the following files of interest in ~/Library/Containers/com.apple.mail/Data/

  • com.apple.mail.plist: This file had some plist keys referencing NSWindow Frame
  • /Saved Application State/com.apple.mail.savedState/windows.plist. Didn't see any specific references to window location info here.

Quitting Mail, moving these files to a safe place and relaunching at least so far seems to have resolved the issue.

I'll test more later,

Thanks


Apple Mail new mail/reply windows always open on different display

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