You didn't say what os you were using but it does sound like LimeWire is set as the app to save your sit files as. In os9 go to your file sharing control panel and make sure that LimeWire is not set for any extentions. ie .sit At one time one version of LimeWire I was using seems to have changed some of these settings in os9 , Mp3 would download as realplayer files sit would download as LimeWire files ect...Changing them to the right application fixed the problem so that it downloaded as the right type file.