If you notice Outlook's layout change out of the blue, it may be because you unknowingly messed with the view option in the menu. There are two other premade views you can find in Outlook aside ...

Outlook lets you change the appearance of your app with a handful of themes, including Light and Dark Mode. You can also set the view to track your computer’s global setting.

Restart Outlook. If the Reset view option is not available in your Outlook version, you may follow these steps: Open the Outlook app on your PC. Switch to the View tab. Click on the Change View ...