Hi Bernd, thanks for reporting. Please try r4171. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Bernd Weigelt <weigelt.bernd@web.de> Gesendet: Samstag, 21. April 2018 18:02:26 An: Development list for mkgmap Betreff: [mkgmap-dev] java.lang.AssertionError: 270: Help needed java.lang.AssertionError: 270 [¹] at uk.me.parabola.imgfmt.app.BufferedImgFileWriter.put1u(BufferedImgFileWriter.java: 154) at uk.me.parabola.imgfmt.app.SectionWriter.put1u(SectionWriter.java: 78) at uk.me.parabola.imgfmt.app.net.RoadDef.writeNet1(RoadDef.java:237) at uk.me.parabola.imgfmt.app.net.NETFile.write(NETFile.java:67) at uk.me.parabola.mkgmap.build.MapBuilder.makeMap(MapBuilder.java:314) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:107) at uk.me.parabola.mkgmap.main.MapMaker.makeMap(MapMaker.java:69) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:290) at uk.me.parabola.mkgmap.main.Main$1.call(Main.java:286) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java: 1149) at java.util.concurrent.ThreadPoolExecutor $Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) [¹] this number is changing, but is the same when building different map styles from one extract. Hi got a lot of messages like this, but only with larger extracts like DACH or Benelux, the germany extract was build without an error The version is mkgmap-r4170 This also happens with the default style Bernd