I'm not absolutely sure how the junk filter works, as I've never used it but I suspect all the files are being identified as junk, and if you go to Tools>options>filters>junk, you can alter the way so called junk is hidden or shown.
I hope this helps. It is also possible files that are not junk are being marked as junk, but it is fair to say that a great many files are junk, but a great many people do not seem to find the junk filter does a particullary accurate job. It will only do the job you "train" it to do ..roughly speaking
