Thank you to all who have responded. Here are some more details. My favourites work fine using Sentinel. I open ARC536, connect my scanner to my computer, download information via Radio Reference, save these systems in ARC536, "read" data from my scanner to ARC536. All appears in ARC536. I then "write " data to my scanner. If I then "read" again all the data (old and new) appears on ARC536. I then eject my scanner from the computer. Turn the scanner on again and "nothing to scan" appears on the scanner. If I go to the "Manage Favourites" there are no favourites listed. If I go to "Select Service Types" I am not able to turn any On or Off. If I reconnect scanner to computer and open ARC536 there is nothing in the scanner to "read" back to ARC536. I then have to reload my favourites from Sentinel to the scanner. There are HPD files in my BUTEL folder in my C drive. There are also HPD files shown on the SD card on the scanner. It just seems as if the scanner will not read the HPD files. Can someone tell me what I am doing wrong please. I am not very good with computers or technology. I'm still back in the analogue days. Thanks