This isn't completely accurate. The Windows file dialog will not but the Win32 api does. Specifying a path such as foo\\bar in the shell for example will work.

This isn't completely accurate. The Windows file dialog will not but the Win32 api does. Specifying a path such as foo\\bar in the shell for example will work. The exception is if the multiple slashes appear at the beginning of the path. Windows accepts UNC paths which begin with double slashes. It will not normalize multiple slashes into double slashes at the beginning of a path but any following multiple slashes will be normalized to a single slash.