A method and apparatus for converting ASCII path names to parsed path name structures (22B, 32B) provides downward compatibility so that program modules written for modern operating systems which provide parsed path name structure inputs may be run under older operating systems which provide ASCII path name inputs. The method includes, in its most basic form, the steps of converting the prefix and file name of an ASCII path name to a unicode string (22A, 32A), then converting the unicode string to a parsed path structure (22B, 32B). In a preferred embodiment of the invention, the method is implemented in compiled object code written in the "C" computer programming language. The object code defines a parsed path structure, allocates buffers for stack variables, creates various pointers for scanning and counting functions, determines whether or not Uniform Naming Convention is used for the ASCII path name, converts the ASCII code to a unicode string, and then via scanning and counting, converts the first two character spaces in the unicode string to unicode numbers which indicate total string length and prefix length, respectively, and converts every other backslash character within the unicode string to a unicode number which identifies the length of the name component of the string which follows that particular number.