Instructions apply to macOS 10.15 (Catalina) to 10.7 (Lion).
smack the first message as part of the group.
Press and hold theShiftkey.
While holding theShiftkey, nudge the last message in the range.
All the emails between the first and last message you chose are highlighted, indicating that they are selected.
you could move, filter, trash, print, or take another action on them all at once.
While holding down the Command key, click an unchosen message to add it to the selected range.
The same holds true for emails not currently selected; theCommandkey selects them.
They may be interspersed randomly among many others.
throw in a search termsender name, subject, or text entryin the MailSearchbar.
PressCommand+Ato select all the messages in the search results.
