Hold down the Option (Alt) key on your keyboard when you click the green maximize button. The window will then zoom the OLD way - i.e., it will not go into full-screen mode. Use a free, third-party app called BetterTouchTool. Hover over the window’s green circle, then select the appropriate option. In Catalina, the green button does more than go full-screen. Click and hold to see the new options. You can also move your Mac’s Dock to.

Disable Full Screen Apps Mac Store
Disable Full Screen Apps Mac Os

If we’re being honest, the release of macOS Catalina has not been quite as graceful as Apple may have hoped. This iteration was expected to be the largest in some time considering the introduction of Catalyst applications.

Contents

2 How to fix Mail opening in Split Screen
3 Conclusion

Disable Full Screen Apps Mac Store

One frustrating issue has been when the Mail app opens in split screen all by itself.

Mail opening in Split Screen on macOS Catalina

This bug may not be exactly new to Catalina, but the Apple Mail app has been wreaking havoc on users for quite some time. Whenever a new version of macOS is released, there are expectations that “major” bugs would be fixed. In the case of Mail opening in Split Screen, that is simply not the case.

Notably, the problem seems to occur if you are working in a fullscreen of another application. An example of this may be browsing Reddit or watching YouTube in Safari in full-screen mode. Then, seemingly out of nowhere, the Mail app decides to just open itself in a split-screen view.

This seemingly occurs due to some bugs found when you have Gmail connected to Mail. Every once in a while, the authentication between Google and Apple Mail will seemingly fail. This causes Mail to open up on its own, causing you to re-authenticate the login.

How to fix Mail opening in Split Screen

Since the bug is related to Gmail, you’ll want to go through and remove the account from Mail before doing anything else. Here is how you remove an account:

Open the Mail app on your Mac
Click Mail in the menu bar
Select Accounts from the drop-down
Highlight the Google account you want removed
Tap the “-” button on the side
Click Ok to confirm

Create an App Password for Gmail

This will remove the Google account from Mail, but you aren’t done just yet. The next step you want to take is to enable two-factor authentication (2FA), and create an “App Password” to use with Mail on macOS Catalina.

Open your browser and navigate to your Google Account Security Settings
Scroll down and select 2-Step Verification
Login and confirm your Google account email and password
Toggle 2-Step Verification On

From here, you are given the option to either use a Google prompt, or through a text message with verification codes. When you use a Google prompt, you must have the Google app installed on your phone, and a notification will arrive confirming that you are logged in.

When completed, go back to the main Security Settings page and select App Passwords. In the box, hit the first drop down and select Mail, and in the second box select Mac. Then tap Generate. This will create a password only to be used with your Gmail account along with the Mail app on your Mac.

Get Gmail back in the Mail app on macOS Catalina

Now that the App Password has been generated, you need to open the Apple Mail app on your Mac. Then follow these steps:

Click Mail in the menu bar
Select Accounts from the drop-down
Click the “+” button at the bottom
Select Other Accounts from the list of options
Select Mail account
Enter your Gmail email account and the App Password that you created earlier
Tap Sign In

After you have signed in, the Mail app will ask whether you want to sync Mail and Notes with this account. Leave Mail checked, and you can either choose to sync Notes or not, then press Done.

Now that the account has been added, it will take some time for the Mail app to sync the data between your Gmail account and the app itself. However, once completed, you should not run into anymore instances of macOS Catalina’s Mail app opening itself.

Conclusion

There are far more bugs and quirks when it comes to macOS Catalina than Apple would like to admit. We are sure that these issues will be rectified with future incremental updates. As is the case with many software releases, you can either choose to upgrade and file bug reports, or just hang back until many bugs have been squashed.

If you continue running into issues with macOS Catalina, sound off in the comments below and we’ll be more than happy to assist. As for the Apple Mail app, let us know what you think about the upgrades provided or if you have been using another client such as Spark or AirMail.

Andrew is a freelance writer based on the East Coast of the US.

He has written for a variety of sites over the years, including iMore, Android Central, Phandroid, and a few others. Now, he spends his days working for an HVAC company, while moonlighting as a freelance writer at night.

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