property secondsInOneDay : 86400
tell application "Mail"
set theInbox to mailbox "Inbox" of account "Exchange"
set dateToday to current date
set firstMessage to 1
set lastMessage to (get count of messages in theInbox)
repeat with thisMessage from lastMessage to firstMessage by -1
set currentMessage to message thisMessage of theInbox
set messageDate to date received of currentMessage
set timeDifference to dateToday - messageDate
if timeDifference ≥ secondsInOneDay then
set archiveMailbox to (mailbox ("Exchange inbox archive" as string))
move currentMessage to archiveMailbox
end if
end repeat
end tell