I'm using Newsbin 6.20 (and just switched to Newsbin 6.30b2 - same problem).
If I exit Newsbin halfway through a download, and then restart Newsbin I get problems. Newsbin detects the parts already downloaded as duplicates and "fails" the entire download (including the not-yet-downloaded parts), which moves it to the "Failed Downloads" tab.
If I move the not-yet-downloaded parts back to the download list, everthing just repeats - *all* of the parts are moved back (including the already-downloaded parts) & duplicates are detected, but this time it tries to download the already-downloaded parts a second time!
I finally found that I could manually pause the already downloaded parts, and then let the not-yet-downloaded parts finish.
I'm sure this behavior isn't what was intended. Is there a switch setting or something else I'm doing wrong?