Vagrant syntax for adding existing local box
Syntax provided below can be used on windows to add existing local vagrant boxes.
$ vagrant box add custom32 file:///f://Vagrant//precise32.box
In the above command custom32 is the name for the vagrant box and file:///f://Vagrant//precise32.box
is the
locally available box. This box was downloaded from internet and placed locally on f drives Vagrant folder.
Also see the screenshot below: