Perhaps I can help ease some of the frustration by restating a few things. I am going to do it in English but if a translation is needed, then I can provide that.
Stefan, the Garmin unit does not have a native way to show corrected coordinates as part of its geocaching features. Hans is discussing a trick that can be used where a POI is placed at the exact same coordinates so that two symbols end up superimposed. This creates the impression that there is a corrected mystery symbol. If you select that on the map in the Dakota, you will note that the unit tells you that there is both a geocache and a POI at this spot on the map. The geocache symbol is the one in the gpx file in the folder GARMIN\gpx; the POI is in one of the files (with extension .gpi) within the GARMIN\poi folder.
If you have exported as discussed, and both the .gpx and .gpi files are present, then this should be happening. If it does not seem to be happening, then find one of the geocaches that has corrected coordinates on the map and zoom in at that spot; at some zoom level the corrected coordinate symbol should appear. It does not appear at all levels unless you set that up with the unit's "Setup Map", "Zoom levels". If you zoom levels are all set to Auto then you will see the POI only when zoomed in very tight.
Also, Stefan, we currently have November 2015 which may be news to you
since your files in the image above are from several months ago. I suggest you export only to the SD card, but not both the SD card and the internal memory because this will cause confusion. To prevent the confusion you are having, I suggest you do as Hans suggested: delete all the gpx and gpi files on both the SD card and the internal memory (if you want to back them up first to your computer, then that would make sense). Before doing anything else, reboot the Dakota with these folders empty. Verify that no geocaching icons are showing and now attach the unit to your computer and run the Garmin Export macro to load to the SD card within the Dakota (not the internal memory). Be sure you include at least one cache with corrected coordinates and then check to see if it is working as designed. Let us know if this helps.
Stefan, the Garmin unit does not have a native way to show corrected coordinates as part of its geocaching features. Hans is discussing a trick that can be used where a POI is placed at the exact same coordinates so that two symbols end up superimposed. This creates the impression that there is a corrected mystery symbol. If you select that on the map in the Dakota, you will note that the unit tells you that there is both a geocache and a POI at this spot on the map. The geocache symbol is the one in the gpx file in the folder GARMIN\gpx; the POI is in one of the files (with extension .gpi) within the GARMIN\poi folder.
If you have exported as discussed, and both the .gpx and .gpi files are present, then this should be happening. If it does not seem to be happening, then find one of the geocaches that has corrected coordinates on the map and zoom in at that spot; at some zoom level the corrected coordinate symbol should appear. It does not appear at all levels unless you set that up with the unit's "Setup Map", "Zoom levels". If you zoom levels are all set to Auto then you will see the POI only when zoomed in very tight.
Also, Stefan, we currently have November 2015 which may be news to you
