A vault is a repository where documents and files are stored and managed. Autodesk Vault is a data management system that offers file security, version control, and multi-user support.
The Autodesk Vault add-in enables you to perform common vault functions on all file types compatible with Autodesk Navisworks. You can organize all of your files and keep them in one location for easy access. All file versions are retained, so you never misplace or replace past versions. The vault stores each version of a file, along with all the file's dependencies, giving you a living history of the project as you work on it. The vault also stores file properties such as the user name, date, and comments for rapid searching and retrieving.
If you have installed the correct Autodesk Vault client, but the Autodesk Vault add-in is not shown on the Autodesk Navisworks interface, select the Show in User Interface check box in the Options Editor 
Tools Vault.