To me it seems that either we do something wrong, or Mapsource cannot handle very detailed places. Try compiling Australia from Geofabrik (I used maxnodes=1300000 - so smaller than default 16...) with the following commandline: start /low /b /wait java -enableassertions -jar -Xmx4200M mkgmap.jar --max-jobs=2 --reduce-point-density=5.4 --reduce-point-density-polygon=4 --suppress-dead-end-nodes --index --delete-tags-file=deletetags --blacklist-tags-file=deletetags --adjust-turn-headings --ignore-maxspeeds --ignore-turn-restrictions --remove-short-arcs=4 --location-autofill=1 --description=openmtbmap_%abr%_%date% --route --country-abbr=%abr% --country-name=%country% --mapname=%mapid%0000 --family-id=%mapid% --product-id=1 --series-name=openmtbmap_%abr%_%date% --family-name=mtbmap_%abr%_%date% --tdbfile --overview-mapname=mapset --area-name=%country% d:\garmin\mkgmap_680\maps\%mapid%00%tile%.osm.gz At the latest on resolution=24 it crashes. If I use --generate-sea=no-mp;extend.... then it already crashes on resolution 22 (zoomlevel 700m). Simply center onto the city POI of Melbourne and zoom in. Same problem exists for Greece and Athens. (it's not related to the TYPfile - Mapsource also crashes without registered typfile). Reports I got indicate that the maps not only crash Mapsource but also BSOD Garmin GPS (though no damage done, except restart needed).