When I uploaded new POI's to my Garmin, it deleted the ones I originally had in there. Why is this?
Keep all your POI files in their original directories on your computer, and just update the new poi files that you want, then use POI loader to load them to your GPS.
POI loader creates ONE file called POI.gpi then sends that to the GPS which has all your updated new files included.
If you only use the new poi files and load them, that is all you will end up with in the GPS..........
All is explained here: