Garmin wrote me back. No surprise now what they told me 
Do you have a data card in the GPSMAP 60CSX ? If so I would recommend removing the card, if you do not get the continuous beep after removing the card then the card may be corrupted and would need to be reformatted.
Guy

Do you have a data card in the GPSMAP 60CSX ? If so I would recommend removing the card, if you do not get the continuous beep after removing the card then the card may be corrupted and would need to be reformatted.
Guy