Thanks, @Drakous79. @glutmate Those options seems to have nothing to do with autocompletion (at least that is what UDK docs sad about them). AUTODEBUG: Perform auto debugging. Attach the UnrealScript debugger and break at the first bytecode encountered.LOG: When used as a switch (-log), opens a seperate window to display the contents of the log in real time. When used as a setting (LOG=filename.log), tells the engine to use the log filename of the string which immediately follows.More command line arguments and their descriptions can found here: https://udn.epicgames.com/Three/CommandLineArguments.html