At recording own CD or DVD, or is simple at general cleaning of garbage on your hard disk it is necessary to delete all copyes of file, by leaving on the disk only original. For the solution of this problem is intended the program Stereo Scan. By the working the program scans the disk in searches of files with identical contents. And the program finds ALL copyes of the file without dependence from them names. In difference from other similar programs, results of searching represents as a tree, where the roots are present by groups of files with identical contents, and branches - files. Such representation of results of searching of double files is closest to style of human thinking, and grants fast and intuitively is clear to supply processing of results. Our program uses the advanced algorithm of searching for double files. Main barriers in searching of double files is: 1) huge number of necessary file comparisons; 2) high load on the gear of the hard disk. Our program is overcoming these barriers. The algorithm putted in the fundamentals of work this scanner, makes a comparison of files, only if the files, at least, are similar, and majority of files on the hard disk are unlike against each other, and as the corollary the program not only does not compare "unsimilar" files, but even and does not open them. The statistician shows, that on the average file is subjected to a comparison not hundreds and thousands of times, as would be at use of a method "brute force", and on the average 1.5-2 times. Thus, the algorithm of scanning reduces to an absolute minimum of operation of a comparison of files, that hardly reduces a load on your hard disk and considerably accelerates process of scanning. Besides the it is more on your hard disk of files with the identical size, the more our program outrun other similar programs. For example, for a 8000 files by the size on 128Kb the advantage of the program above the similar programs becomes absolute.