Under
Window->Preferences->Drools->Installed Drools Runtimes

The dialog presented to the user (see attached) screenshot - successfully enables the user to create a runtime by referencing the install directory of a Drools runtime. The user defines a name for the new runtime, specifies the install directory, and presses "OK."

If, however, the user opts to create a new runtime, indicates an empty directory for the new runtime, and presses "Create a new Drools Runtime" - an empty runtime is created - nothing is written to disk.