In the German forum (1) a newbe stumbled over this problem. He started to create his map using options --gmapi and --index and finally also wanted a gmapsupp.img, too. So he added option --gmapsupp . Now, with this combination mkgmap doesn't create the mdx file. One has to specify --tdbfile to get this back again, which is really not intuitive. I think both options --gmapi and --nsis shoud imply --tdbfile, or maybe better, we should simply create the index for the requested output files when --index is given. I never understood why adding option --gmapsupp suppresses the creation of the pc index file(s). Is it really only because the current implementation requires more memory? (1) https://forum.openstreetmap.org/viewtopic.php?pid=736898#p736898 Gerd