What do you mean "open a folder". Are you implying displaying it in the windows explorer ?
Are you using NW.JS and its dialogs or are you attempting a browser to open a folder on the local hard drive ?
Please be more specific on what you are wanting to exactly achieve and under which circumstances.
NW.JS can open a folder using the "Show folder dialog" action for example.
I need to open a specific folder in NW.js, showing the actual folder content directly from the windows browser. Or if the dialog is the only option, is there a way to tell it to use a "default" place?