Mail applescript dejó de funcionar en Yosemite

Gracias al comentario de Buscar lo he solucionado:

tell application "Mail"
set accountlist to the name of every account
try
    repeat with n from 1 to (the number of items in accountlist)
        set _msgs_to_move to (a reference to (every message of mailbox "INBOX" of the account (item n of accountlist) whose flagged status is false and was replied to is true))
        set _msg_list to contents of _msgs_to_move
        if (_msg_list's length > 0) then
            move _msgs_to_move to mailbox "messaggi letti"
        end if
    end repeat
end try
end tell

¿Obtiene los mismos resultados utilizando

tell application "Mail"
set _msgs_to_move to every message of inbox whose flagged status is false and was replied to is true
    log (count of _msgs_to_move)

end tell