In Lightroom 5, whenever you create a new catalogue and subsequently try to import photos using the Add Folder option, the file browser dialog by default is supposed to open to the folder the new catalogue was created in. However, you might experience a possible annoyance where Lightroom keeps opening a particular folder regardless of how many times and where you create new catalogues in.
To fix this, open up the Lightroom 5 Preferences.agprefs file which can usually be found in the C:\Users\<username>\AppData\Roaming\Adobe\Lightroom\Preferences folder (sorry, I don’t know what the Mac equivalent is!) and delete the line that starts with
Note: the value in this line should match the folder that Lightroom always browses wrongly to by default.