Mail app opens randomly in MacOS 10.14.5 [duplicate]

I have mail app open in background i.e. no window open. A new window randomly pops up without any conscious trigger by me. No new mail would have come.

Once it happened while I was in full screen mode of another app and the mail app split the window in half and got opened. This happens even when I am working in non Full-screen mode.

I presume that it has connection with notifications but other reasons are also welcome.

Once, it popped up above other apps, and some accounts were transitioning from offline to online state. I cannot confirm about Google account as one answer mentions.

Why might this happen but more importantly, how to stop this other than quitting it properly? I want to stop it from opening it altogether, not only in split view.

The answer to Mail opens a window randomly in split screen with my fullscreen window recommends to untick a Mail preference. Unfortunately I get the behaviour even thought the preference is unticked, so I look for other solutions.

Solution 1:

This was happening to me for a while, and it became very annoying. I found that if I force closed it and turned the laptop off and on, it worked. If that continues to happen, turn off the WIFI connection and do the same steps.

As to stop the behaviour in split mode, unchecking the checkbox in mail preferences for "Prefer split view while opening messages in full screen view" helps.

Solution 2:

I have been suffering from this problem for months. I tried so many solutions (for example https://www.reddit.com/r/MacOS/comments/7d81ak/solution_for_those_who_have_the_mail_app_randomly/ ) and so on.

This really irritates when I am watching a movie in fullscreen and the Mail app pops up randomly and splits the screen.

Possible workarounds: - Turn off desktop notifications as suggested by @Casimir - Turn off the split window of Mail when full screen (Prevent Mail.app from opening in split view)

In the end, nothing worked for me.

Temporary workarounds:
- Keep Mail app opening and make the window very small all the time. - Open multiple windows and keep Mail window open in one of the windows. - Also, If you can hide Mail.App by Cmd H or click on Mail at top left of you desktop, click Hide menu.

I suspect this bug is due to mail.app checking new emails periodically and each time wanting to be fullscreen. I have also added my vote on apple service and still waiting for a permanent solution.

Update
As suggested in comments by OP hiding the Mail.app (cmd h) is also an alternative, but still, we have to open the app all the time whenever we are running the computer so as not to be offended by intermittent apperance of Mail.app.

Solution 3:

I've been experiencing this issue for a week now. The mail app pops up by itself in split view next to my full-screen browser several times a day. It hasn't happened in over a day now after following the steps in this reddit post according to which the culprit may be Google calendar. If you're using it, try changing the notification settings as follows:

1. Login to Google Calendar at https://calendar.google.com.
2. Click the settings gear icon (upper right-hand corner) and select “Settings” from the drop-down menu.
3. Under the "General" tab (open by default), scroll down to "Event settings".
4. Open the "Notifications" drop-down and switch from "Desktop notifications" to "Off" ("Alerts" might work as well).