Understand hidden files and folders
Expression Web keeps track of all files that are associated with your Web site. This information is kept in 2 hidden folders, which you should be careful not to move or delete. These hidden folders and their contents do not appear in the Folder List task pane, but they will appear in Windows Explorer if you have the option set in Windows Explorer to display hidden files. Metadata is information about the document in your Web site. The _vti_cnf metadata folder contains information about every file in a particular site. Expression Web uses this information to determine the location of links within the site. The _vti_pvt metadata folder stores several files that provide information, among other things, to configure the initial settings for Expression Web.