Hi all, not sure what that means but I am also able to reproduce the problem when I create the DEM data with Franks program BuildDEMFile using my modified hgt file containing some voids. The voids are far from the route that causes the crash, somewhere around N52.24588 E10.50330. I've uploaded a new test set here: http://files.mkgmap.org.uk/download/412/baddem6b.7z I hope Frank has an idea where to fix this. ciao, Gerd