BigSur Mail

jrw127 wrote:

After updating to BigSur on my MacBook Pro, I accidentally deleted the "all" mailbox from the sidebar. How do I get it back?

https://support.apple.com/guide/mail/whats-new-in-mail-cpmlwn/mac

Howdy,

It sounds like you removed the "All Inboxes" from your Favorites in the sidebar.

To add it back, hover over the Favorites heading and click the (+) symbol that appears to add back a Favorite.

The Add Favorite option has a pop-up menu where you can select "All Inboxes".

After adding it, you can move it back to the top by dragging it back up.

See Use the sidebar in Mail on Mac

ivan