I, personally, have not seen any files which were labeled incorrectly except some pornography in which case I don't really care. The request for previewing files, under whatever motivation, is not a very feasible thing to implement.

1) Many partial files can't be previewed at all.
2) Many partial files can't be previewed without "fixing" them first.
3)Very very few partial files can be previewed at all when not starting from the beginning.

XoloX would need a database of file types, whether or not they can be streamed from the middle, whether or not they can be fixed, and either bloat their software with fixing tools or require that you use the ones they ask you to.

Mp3 are the only files I can think of at all who's contents can be previewed from the middle soemwhere... and those are small enough that it doesn't matter.

Mpeg: Can only view first segment.
AVI: Can only view first segment and must use a partial file fixer or with file properties (This can crash system when it tries to read data beyond what's downloaded).
AVI (divx): Can only view first segment and must use a partial file fixer.
rm,ram: can't vew at all until done and can't fix if it's surestream.
Zip: Can only use the fisrt segment, and must fix with partial file fixer.
jpg, gif, bmp, etc: Can only view the first segment, but are small enough that who cares?
ISO,BIN: ??? anyone know?

Ok, so suppose you want to preview the movie you are downloading... it says you have 360 MB downloaded, but how much of that is in Segment 1? For me it's usually either very little, or a whole lot. remember that XoloX has to make a copy of the segment because it might want to append to it, and can't if it's locked by an application, and the file wouldn't work when done if you modified the data to view it.

So if you feel you MUST preview your files, for whatever reason, copy segment 1 of the job soemwhere, rename it to have the propper extension (remember, people often misname their AVI's to MPG and vice versa, so find a media type checking util), try and execute it. If it doesn't run, go find utilities that can fix it, download those, fix the file, try to view it again.