Thanks for your help. Well, I don't have any mods beside interstellar installed. The interstellar mod is the newest version. Without the fnmethaneTank I can start KSP, and a short test shows that KSPI parts are available at the VAB. I have the following folders and files in there: HexCans ModuleManager_1_5.dll Squad TreeLoader WarpPlugin .x86 is the 32 bit version, and .x64 is the 64 bit version. The linux version of KSP already supports 64 bits (but I don't think that this should matter, since KSPI runs at the 32 bit version at windows). Maybe this could be an argument to get some KSP players to linux if they want to try a lot of mods ;-) In another log file (the unity one which I didn't know about at the time of my old post) I found the following lines: I tried to have a look in the part.cfg, but didn't find a coma which seems displaced. I think this may be a bug in the part.cfg, but it could also be a bug in the PartLoader. Maybe one of the DEVs could have a look (KSP or KSPI)