Starting in early 2013 or so, Usenet posters began to obfuscate filenames. So instead of seeing a set of files like this in your NZB files or newsgroups:
Some-File.r00
Some-File.r01
Some-File.r02
Some-File.par2
…you now might see something like this instead:
1567849.r00
1567849.r01
1567849.r02
1567849.par2
While this is not a serious problem, it can be inconvenient if you are using an NZB downloader app that hasn’t been updated. What will happen is that after it downloads the files, it will try to unPAR them, but the operation will fail because it won’t be able to find the right files.
However, the PAR2 file will contain not only the correct filenames, but also MD5 hash codes which it can use to rename the files. SuperNZB v4.2.0 and higher can do that. If you want to continue using your old NZB program, you can handle the PARing and RARing processes yourself by using QuickPAR on Windows and MacPar Deluxe on the Mac. Both apps know how to rename obfuscated files. See this page for more info.
Note: In SuperNZB, if you move the PAR2 file up to the top of the Queue you will be able to watch the files get renamed as they are downloaded. Otherwise, the renaming won’t occur until the PAR2 is downloaded.