Migration Assistant from iMac to iMac stalled...

We are using migration assistant to transfer all of our information from our old iMac to our new iMac via Ethernet cord. It started out saying 18 hours remaining. We left it overnight and in the morning it said 6 hours 50 minutes remaining, but it has been stuck there all day (approximately 9 hours). What do we do to fix it and get our information transferred?