Prior to Big Sur, when I deleted an email it went to the "Trash" mailbox in the Apple Mail app.
With Big Sur, it simply disappears (in spite of there being a Trash mailbox in the app).
To find the deleted email I have to go to my Gmail account (which is listed near the bottom of my Apple Mail app.)
I want my Apple Mail Trash mailbox to function again!
Mac mini, macOS 11.0
Hello DaveRich.
Welcome to Apple Support Communities. We understand that you want to know where to find the trash for your Gmail account in the Apple Mail app in Big Sur. We are happy to help.
Please view the section titled “View deleted emails” here: Delete emails in Mail on Mac - Apple Support
Let us know if you have further questions.
Take care.
Hello DaveRich.
Welcome to Apple Support Communities. We understand that you want to know where to find the trash for your Gmail account in the Apple Mail app in Big Sur. We are happy to help.
Please view the section titled “View deleted emails” here: Delete emails in Mail on Mac - Apple Support
Let us know if you have further questions.
Take care.
Per Apple support I went here:
https://support.apple.com/guide/mail/delete-emails-mlhlp1001/mac. (View Deleted Emails)
Using that advice, in the Mail app I went to Mail > Preferences > Account > Selected an account (iCloud, IMAP) > Mailbox Behaviors. In the iCloud portion, "Deleted Messages" had been checked by default. That was the problem.
I checked "On My Mac" and after a reboot that solved the problem. Deleted messages now go to the Mail app Trash mailbox as they had in Mac 10. Some misguided programmer at Apple had made iCloud the default and thus caused the Trash mailbox in the Mail app to become inoperable. Millions of user are going be distressed the same as I was until they learn what Apple did in OS 11.
Apple Mail
