I have a split rar archive, with like 20 parts. Well one part says CRC failed, the file is corrupt. But I know it isn't a bad file, becuase many other people have downloaded the same one, with no problems extracting it. This isn't the first time this has happened lately either, it seems it's becoming repetitive lately. I just upgraded to the latest winrar also, so that's no problem.

EDIT now it's like every odd number file that's having that problem, and other files are having different CRC errors.

Just because others have downloaded the same file and it was OK, doesn't mean your download isn't corrupt.

Try the repair feature in WinRar, or download another copy of the file.

make sure you have the latest version of winrar installed

also,what you need to try is,re-open the original torrent file in another client
sometimes a download which says 100%,isnt actually finished (unlikely though,but at least rule it out)

lastly,use the sfv file which came with it,(every decent uploader should use these)
use a sfv file checker to find out which files are bad,you could always re-download just the bad archives