Why does the 'Untitled mail' page keep appearing on my Mac?

You have made the Tab bar visible in Mail.

Use tabs in Mail on Mac - Apple Support

cathryn189 wrote:

Why is this page keep popping up on my mail?

https://discussions.apple.com/content/attachment/22fece11-3ef4-459b-accc-733f2bc64b97

[Re-Titled by Moderator]

Original Title: Untitled mail page

MacBook Pro 13″, macOS 15.7

?

I don't get it. Old issue, new issue, what changed?

What triggers the this to open a blank tab, what are you doing exactly...what are you trying to do?

ref: Mail User Guide for Mac

I don't use tabs, however you can search the Help menu if in doubt—Tabs(?)

the current Sequoia is 15.7.2

the current Tahoe is 26.1

Keep your Mac up to date - Apple Support