Backup your unit using Explorer, not Home. Yes, 840 is the latest map and you should be able to install but make sure you have the most current application firmware for the model. connect to Home and if a later app is available, Home should let you know.
I made a backup with explorer and installed latest application for my 140s. I haven't install the new map yet. Did I lose quick gps fix going to the 140s? I don't see it. My 130s that I just sold on Ebay had it. Is that the only down side of the 140s vs 130s. I bought the 140s instead of buying new maps for the 130s and I figured IQ routes and lane guidance made the 140s a better unit.
You can get the gps quickfix for your unit by connecting it to Home and updating your unit. If you're doing that and still not getting the file then use Explorer to delete everything in the ephem folder on the unit and, as well, delete everything (all the sub folders) in the ephemeris folder on the computer found here:
c:\documents and settings\yourname\my documents\TomTom\Home\Downloads\Complete\ephemeris\
I used explorer to search for the ephem folder on my 140s and I don't have that file or folder. I do have the ephemeris folder on my TomTom home, it has 16 quick fixes listed. I also have a TomTom 730 that I use with TomTom home too.
update on this, I logged in on TomTom home that I have installed on a different computer at home and I got the quickgps fix on my 140s. Does this mean all I have to get it to work on my other computer is to delete all 16 gps fixes in that ephemeris folder?
I cleaned out the ephemeris folder like you said. Now all is good with my TomTom 140s. I can get quick gps fix with the 140s on my notebook now. I did a the explorer backup and downloaded the new 840 maps too. took a long time but all is good now. Thanks. I like the little 140s