
Previously the equivalent of the "All" folders appeared under the Mailboxes heading in the sidebar, instead of under the Favourites heading where it now sits. The MacBook Air is running Monterey 12.1 and this feature works differently to the implementation on Catalina. You can either view the mails as a single list or expand the directory to see them by individual email account. The All Sent folder, like the All Inboxes, All Drafts etc folders, is a high level directory to the corresponding folders for all of the email accounts active on the pc. This issue has been reported by others, but generally the problem appears not to have been fully understood.

Lost "All Sent" folder in Mail on MacBook Air My Mail "All Sent" folder has disappeared from the sidebar and there appears to be no way to add it back.
