The definition says that an allowed format for the link-location parameter is a “universal naming convention (UNC) path on a server”, though this term is not defined.
Provide a normative definition or reference for a UNC path.
3.17.7.144 te
HYPERLINK 2658(2665)
Proposed Disposition of DIS 29500 Comment CO-0192 (Modified: 2007-12-07) We agree that UNC is not the correct term to use here and propose the following change to Part 4, ยง3.17.7.144 page 2,659. 3.17.7.144 HYPERLINK Syntax: HYPERLINK ( link-location [ , [ friendly-name ] ] ) Description: Creates a shortcut that opens a document stored on a network server, an intranet, or the Internet. When the cell that contains the HYPERLINK function call is clicked, the file stored at link-location is opened. Arguments: Name Type Description link-location Text The path and file name to the document location to be opened as text. link-location can refer to a place in a document–such as a specific cell or named range in a SpreadsheetML worksheet or workbook, or to a bookmark in a WordprocessingML document. The path link-location can be to a file stored location on a local hard disk drive, or the path can be a universal naming convention (UNC) the path to a location on a server , or a Uniform Resource Locator (URL) path to a location on the Internet or an intranet. [Note: Using a URL is the preferred way of specifying link-location. end note] If the path location specified in link-location does not exist or cannot be navigated, an unspecified error is produced when the cell is clicked. link-location can be a string or a reference to a cell containing a string. friendly-name text, number, name The value that is displayed in the cell. If omitted, the cell displays link-location. friendly-name can be a value, a text string, a name, or a cell that contains the jump text or value. If the evaluation of friendly-name results in an Name Type Description error value, the cell displays that error value rather than the jump text. Similar Comments: FR-0464 , GB-0409 , US-0206

Why use UVC when the file: URL schema could be used?
(http://tools.ietf.org/html/rfc1630 and http://tools.ietf.org/html/rfc1738)
Undefined Concepts, Has Dupes