Kein Problem: Apple Script-Editor starten, folgenden Code eingeben:
tell application "Mail"
set v to first message viewer
set a to messages of v
get count of a
set selected messages of v to {}
set mids to {}
set s to a reference to mids
repeat with eachMessage in a
set i to message id of eachMessage
if mids contains i then
if (count of selected messages of v) > 0 then
set selected messages of v to (selected messages of v & {eachMessage})
else
set selected messages of v to {eachMessage}
end if
else
copy i to the end of s
end if
end repeat
beep
display dialog "Finished selecting duplicate messages" buttons {"OK"} with title "Select Duplicates Script"
end tell
Als Programm abspeichern, den Cursor irgendwo auf ein Mail setzen und das Script dann per Mausclick starten.