If you do not have a JRE installed, the launcher will never prompt you do download one or install one from a local directory even if the launcher.ini is setup correctly to do so. This is a problem with the QProcess:execute method of the Qt library. The problem is that the code that looks like: always succeeds even if there is no "java.exe" anywhere on the system. The cause of this is the implementation of QProcess::execute. It's implementation looks like: The problem is that internally, the "start" method uses "CreateProcess" to create the process. Of course this will fail if the program does not exist. But the code never sets the "exitCode" member in this case; it still has the value 0. The cleanup code in "start' sets the "error" member in this case. But since the QProcess is created locally, this member cannot be queried. I've fixed this problem locally by adding a 2 new methods to "launcher.cpp" that look like: and changed all references of QProcess::execute to "Launcher::execute". This works fine now. I can supply a patch. But I would like to know how launcher.exe is built and linked. What compiler chain (MinGW? win32-g++?) Also, how was this linked as when I rebuild, this uses the Qt library with DLL's and now the exe relies on them as well as the mingw DLL.