Get the cutted maps and areas.list file (in order to use -c option) for recreating the problem here: 1. _/http://openmtbmap.org/beta/iceland_osm.gz.zip/_ (11MB): Style-file here: 2. /_http://openmtbmap.org/beta/style-file.zip_/ If i either remove my style-file OR remove --route, then it compiles without problems: java -ea -jar -Xmx6500M c:\openmtbmap\mkgmap.jar --max-jobs=1 %style-file% --route -c c:\openmtbmap\maps\template.%country% Seems that just one more time, my extensive style- triggers an error, that otherwise maybe never shows up (or very rarely). Error only happens when using locator branch. (does not matter if I use my patched locator trunk, or latest from mkgmap.org.uk ). I have no clue how to get the stack trace of mkgmap locking up.