A Mail app for Mac acts as one shelter to sync the mails from all other email accounts without visiting specific websites. For instance, you can sync emails from Gmail, Outlook, etc, and view them in the Mail app.

Sometimes, the applications are likely to bring up errors that are complex to fix, or you just don’t know what to do. Talking about a macOS with the Mojave version, what if you can’t switch to the regular layout?

The issue has been brought up by a lot of people that changing to the classic layout didn’t help either. (Mojave has the classic layout, not Catalina. Keep away the confusion)

The issue as reported is that the Mail app is previewing only two windows consisting of a list of mailboxes and a list of messages. What about the third column that includes previews of mail messages? Don’t worry; you’ve got it! All you need to do is drag the right edge of the mail preview window, and the third column will appear.

Didn’t work, right? You must have tried getting back to the classic layout but failed.

How did the Mail app Change from Mojave to Catalina?

While using the Mail app in macOS Mojave, you must have come across the option for classic layout in the Mail’s viewing preferences. The same is unavailable in macOS Catalina. However, you can switch to the classic layout by making a few changes in the ‘View’ menu.

As you all know, the Mail app has a three-column view: mailboxes, a message list, and mail message preview. Catalina lets you view or hide the column on the right with the help of ‘Show Side Preview’ under the ‘View’ tab. Else, you can hide the preview window by dragging the divider between the message list and preview to the right edge. Now, the fix we’re going to talk about is the divider getting stuck to the right edge.

Have you encountered the same problem? The pointer’s appearance changes as if it’s ready to drag to get back the preview window. Instead, the action can not be performed.

Follow the instructions mentioned below to quickly fix the layout error appearing with the Mail app.

If the Mail app is running, click on the Mail tab on the top of the window.
A drop-down menu will appear. Select ‘Quit Mail’ from the list.
Next, switch to the ‘Finder’ window.
Click on the ‘Go’ menu in the menu bar.
Select ‘Library’ from the drop-down menu.
Open the ‘Containers’ folder.
You’ll see a ‘com.apple.mail’ folder in the window. Drag the same to the Desktop screen.
The last and final step is relaunching the Mail app.
Once you follow all the steps carefully, the three-column view will return, and the Mail app will function just as usual. You can delete the ‘com.apple.mail’ folder from the Desktop after you get what you wanted.

Note: The Mail app will display in the default view. However, you can make changes to the same to reset the application..

SOURCE:- Can’t Switch Back to the Mac’s Older Mail App Layout? Here’s the Fix