RE: Excel files sent to Notes7 seen as .dat Melissa L Snell 15.Oct.10 04:01 AM a Web browser General 7.0Windows XP
Search the notes 4/5 forum as well as this one I think. This is to do with either your settings in outlook or your organization's exchange settings. Can't remember which but there has been a LOT of discussion in the past.
Try searching on DAT and outlook and email and see what you get