How do I open folders in new windows/tabs by default in the Finder in 10.9? In 10.9 Mavericks the default for the Finder is to now open the selected folder in the same window instead of a new tab or window. How do I go back to the old behavior where a new window (or tab) is opened for each folder?
The closest solution is to go to Finder Preferences > General, uncheck the "Open folders in tabs instead of new windows" option, and then use Cmd + double click to open in a new window.

Source: Apple Support Communities - Mavericks Finder - how default to "double click opens new window"?