Nzbval is a free utility that you can use you test an NZB file against your news server and verify that all of the parts exist before you start downloading. It can save you a lot of time because you can avoid downloading from .NZB files that have missing parts. Missing parts can ruin a download, wasting time and bandwidth, and nzbval is designed to prevent that from happening. Nzbval is free for noncommercial use.