SuperNZB – NZB Downloader

Super-NZB is an NZB-file downloader for Windows and Mac OS X. It will open your NZB files, download from your Usenet server, and automatically run PAR and RAR to extract the files.

Download for Windows (10, 8, 7, Vista, XP)
Download for Mac OS X

Download for older PowerPC Macs running OS X

Make sure to have an NZB file on hand!

Mac users: Download with Apple’s Safari browser if your current browser doesn’t understand DMG files.

The current version of Super-NZB is: 4.2.4


SuperNZB-64 is the new 64-bit version of Super-NZB and is about twice as fast! Most people have 64-bit computers now, so give it a try!


Go to the SuperNZB help page.

SuperNZB Technical Specifications.

Step-by-Step Guide to NZB Files.

Click here if you are upgrading from an older version.

Download Over One Gigabyte Per Hour!

Using a commonly available 5,000 kbps cable modem, SuperNZB can download more than one gigabyte per hour! Don’t believe it? In the screenshot below, you can see SuperNZB (which looks identical on the Mac) finishing up a 1.16gb set of RAR and PAR files in about 35 minutes. Using the six connections to the Usenet server, and a 5mbps cable-modem, it averaged a speed of 4,567Kbps with a peak at 7,112Kpbs (due to hardware compression in the modems.)

Click picture to enlarge:

SuperNZB Screenshot

The Downloader

SuperNZB’s Downloader Window can be opened from the File Menu.

The list of Usenet servers that you see on the Downloader is created when this window opens up. It looks at the servers you have set up on the Servers window, sees which ones are “active” and then uses the “connections” number to create the list.

Each line you see is a “connection” and each server will usually have more than one connection. SuperNZB takes the server name you entered, and then adds a dash, and a number for each connection to create the server name you see here. So, if you have entered the TechSono server with five connections, you will see:


If you change something on the Servers window, you must close the Downloader and then re-open it to see the changes. You can turn a connection on-and-off while the Downloader is running via the check-box at the left.

The State column shows what the connection is doing. First, it connects to the server, then it sends your username, then your password, then asks for a post, receives a post, etc.

The Errors column shows the number of errors the server has returned on that connection. These are server & handshaking types of errors, and don’t indicate whether or not the file being downloaded is corrupt. They are usually nothing to worry about, but are an indication as to how reliable the server is. Read more on the Error Handling page.

The MB column shows the total number of megabytes downloaded by that connection.

The Speed column shows how fast the current post is being downloaded. This usually starts out slow and then increases since there is some time-consuming handshaking that must go on as SuperNZB asks the server for a post.

Next to the Speed column are progress bars, which show you how much of the current post has downloaded as a percentage. Half-way means 50%, etc.

To the right of the progress bars is a message area where SuperNZB will tell you some further details about what the connection is doing.

The combined speed number is the overall speed of all the connections put together. Ideally, this number will hit, and slightly exceed, the rated speed of your internet connection. Your ISP may be able to boost your speed without you having to do anything, or even telling you they have done so. Sometimes you will need a new modem to take advantage of their faster service, so it pays to call them from time-to-time and see what the latest deal is. If SuperNZB isn’t going as fast as you would like, you can add more Usenet servers by subscribing to a service such as Easynews.

To see further stats, open the Stats window from the File menu.

When you click the Stop button, SuperNZB will finish the posts it is working on before logging off of the connection so as not to waste any data.

Test Your Usenet Server

To investigate connection problems to your ISP’s Usenet server, go onto SuperNZB’s “Help” menu and then to “Test News Server.”

Select the server in question from the pop-up list, and then click the Connect button. You can copy-and-paste any error messages and send them to your Usenet Service Provider. The lines that begin with an arrow show the command that SuperNZB is sending to the server. The line below a command is what the server has returned in response.

For commands where the server sends more than one line, such as the “help” command, you must look for a period on a line by itself – that will be the last line that the server sends.

If you made a typo when setting up the server, close the Test Server window first before correcting the typo on the Servers window. The Test Server window will not automatically pick up changes made on the Servers window, so you have to close it, and then re-open it, to test again.

If you can connect successfully, send the “help” command, and get back the list of commands from the server, then everything is working properly. However, during this process, you are only talking to the main server. A large server farm will have many computers, and if one of them is malfunctioning, you won’t get an error message until you try to access one of the newsgroups stored on that server. So, what you need to do is use the “Group” command like this:


The server should send back a response like this:

211 566032 497526 1063557

If you don’t see something like that, send whatever the server responds with to your Usenet Service Provider. They will want the exact text of the error message so that they can track down the problem.

Versions & Upgrading

The current version of SuperNZB is v4.2.4 for Windows and newer Macs with Intel CPUs.

For older Macs with PowerPC CPUs, the last version was v4.0.6.

Windows Upgrade Instructions

If you are running version 3.0 or higher, you can just run the installer. If you are upgrading from a version older than 3.0, this version of SuperNZB will not be able to read your SuperNZB.sdb database file where your settings are stored. You can re-enter your news-server info, or you can just as quickly convert your current SuperNZB.sdb database file by following the instructions on this page.

Mac OS X Upgrade Instructions

If you are running version 3.0 or higher, copy the new SuperNZB folder to your hard disk, then drag your existing SuperNZB.sdb database file into the new folder. Then you can throw away the old folder. If you are in the middle of a download, you should also copy your Parts and Downloads folders into the new SuperNZB folder.

If you are upgrading from a version prior to 3.0, you can convert your current SuperNZB.sdb database file to avoid having to re-enter your news-server data. Click here for conversion instructions.

Recent Version History

    Version 4.2.4 – Released on May 4, 2015.

  • One small UX bug fixed.
    Version 4.2.3 – Released on April 21, 2015.

  • Minor changes to the plumbing only.
    Version 4.2.2 – Released on February 16, 2015.

  • Links to Easynews and IPVanish were added to the Servers window.
    Version 4.2.1 – Released on April 7, 2013.

  • This version has further refinements for handing obfuscated filenames. See the note below.
    Version 4.2.0 – Released on April 6, 2013.

  • Code was added to handle obfuscated filenames which were preventing automatic unPARing and unRARing. Read more here.
    Version 4.1.1 – Released on March 8, 2013.

  • This version fixes a an obscure bug in the yEnc decoder that would cause SuperNZB to crash.
    Version 4.1.0 – Released on February 23, 2013.

  • This version fixes a long-standing, mysterious bug. The program would crash if you closed the Downloader window while it was still downloading. However, the crash would not occur until a few minutes later, which made it very difficult to catch.
  • Another bug was also fixed where sometimes the Downloader window would keep popping back open after you closed it.
    Version 4.0.9 – Released on February 16, 2013.

  • The error-handling code has been improved to recover better from closed server connections. So, if you have an unreliable Usenet server, this version will have a better chance of completing your downloads.
  • A new “Repair Database” command has been added to the “Help” menu. Database corruption can cause odd errors. So, if you are having a problem, this command might be able to fix it. The command will also compact the database file.
    Version 4.0.8 – Released on May 15, 2012.

  • Fix for the braindead v4.0.7.
    Version 4.0.7 – Released on May 15, 2012.

  • Minor bug fixes.
  • This version introduced a new bug, so it was replaced by v4.0.8 on the same day. If you have this version, you should upgrade.
    Version 4.0.6 – Released on October 13, 2011.

  • The “Force File Decode” feature on the Commands menu can now decode more than one file at a time. Just select all the files needed in the Queue window, and then activate the command. This will be a big time-saver the next time you get a messed-up NZB file that contains more parts than actually exist.
  • Additional code was added to handle a few more scenarios where there are missing files on the server, bad information in the NZB file, etc. Thanks to everybody who reported these scenarios so that we could address them.
  • The Mac version now has a separate DMG file for older PowerPC Macs. If you have such a system, make sure to download the right DMG from the SuperNZB home page. There is only a small trickle of people still using PPC Macs, so by making separate DMGs, we were able to chop the previous “fat binary” in half from 10mb to 5mb. And the vast majority of users now have a quicker download.
    Version 4.0.5 – Released on July 2, 2011.

  • A major overhaul of the download engine has been done. Usenet servers now allow dozens of simultaneous connections. And while SuperNZB had no problem handling large numbers of connections, it did have trouble when people used more connections than their internet connection and/or computer could handle. In those cases, many time-out errors would occur, slowing down the download process. This version is designed to handle that condition much more smoothly. The moral of the story is that, gazillions of connections are mostly an advertising gimmick. In most cases, SuperNZB will max out your internet connection with only a handful. And if you see a lot of errors, you might be able to download faster by reducing the number of server connections that you are using. This overhaul will also benefit those of you using low-quality servers, as error-handling in general has been optimized.
  • On the Settings window, there are now options for automatic deletion of RAR & PAR files. This was surprisingly difficult to implement because newbies will often go to a site like, tick a bunch of boxes, and create an NZB file containing god-only-knows-what. So, it is almost impossible to have the program automatically delete files perfectly. If you are downloading a “standard” NZB file, with the normal compliment of RARs, PARs, SFV, NFO, and SRR files, then this feature will work smoothly. Otherwise, you might see a file or two left over in the Downloads folder.
  • The unRARing process now preserves the folder structure inside the RAR archive. This will be especially helpful when downloading audio files. Previously, the program would just throw all of the files into the Extracted_Files folder, sometimes causing file collisions.
  • The program now has a new NZB-file parser. Previously, it had a customized parser that could parse large NZBs without loading the whole file into RAM. But now that has decided to produce ridiculous files with no end-of-line characters, we have switched to a standard XML parser based upon Expat. It will use more memory, but SuperNZB can now handle files from again.
  • A few other small bugs were fixed.
    Version 4.0.4 – Released on April 21, 2011.

  • Additional Decoder windows are now saved from session-to-session.
  • Moving the app window on Windows 7 is now smooth. It was jagged in previous versions.
    Version 4.0.3 – Released on April 10, 2011.

  • Fixed a memory-leak bug affecting versions 4.0.0, 4.0.1, and 4.0.2.
  • Other minor changes, and bug-fixes.
    Version 4.0.0 – Released on February 23, 2010.

  • SSL options added.
  • The program will now identify multiple par2 files in the Queue. It will process them as soon as all the files for that par2 set have been downloaded instead of waiting until all files in the Queue are done.
  • SRR, MP4, and BMP file types added.
  • Other minor changes.
    Version 3.2.1 – Released on January 18, 2008.

  • “Force File Decode” command added to Commands menu.
    Version 3.2.0 – Released on December 11, 2007.

  • SFV Checker Window added.
  • Test Server Window added.
    Version 3.1.1 – Released on November 30, 2007.

  • MKV has been added as a default file type.
  • Other minor changes.
    Version 3.1.0 – Released on June 23, 2007.

  • SuperNZB can now check your NZB file to see if its files are present on your Usenet server.
  • The program can now be launched by dropping an NZB-, RAR-, or PAR file on its desktop icon or shortcut/alias.

Manual Pages

  1. Downloader Window
  2. Queue Window
  3. Decoder Window
  4. Import Window
  5. Servers Window
  6. Error Handling
  7. File Types
  8. Filenames
  9. Folders
  10. Folder Totals
  11. Hold Window
  12. RAR Window
  13. PAR Window
  14. PAR Job Manager
  15. RAR Job Manager
  16. Move Job Manager
  17. The Check-Files Window
  18. Debug Mode
  19. Test Server
  20. SFV File Checker

Use SuperNZB for free.

SuperNZB contains a free RAR file decoder, a free PAR & PAR2 file decoder, and a free SFV file checker.

14 Responses to “SuperNZB – NZB Downloader”

  1. Alexis Livanos says:

    I reloaded SuperNZB because it got corrupted and I do not remember my registration key. Please help/resend

  2. Steve says:

    Is there a way to ‘import many’ NZB files and have each NZB’s downloads output to separate download folders?

  3. Ray says:

    I just installed this and I want to know how to download NZB-Files?

  4. Ray says:

    OK but I have imported NZB-Files but they don’t seem to download anyway.

  5. Ray says:

    Socket error: 103

    • Matt says:

      The 103 error indicates some kind of network problem. Normally, if you reboot your computer, modem, and router, the problem will go away

  6. Ernie Tredenick says:

    I don’t see my earlier e-mail displayed so here goes again: I recently had to replace my old laptop and am wondering since I still have my registration key can I just download supernzb and use that registration key to activate the progarm on my new laptop?

  7. Scott says:

    I just purchase SuperNBZ64 bit and like it a lot, download speeds are amazing. I did notice that it does not get rid of the par2 files when the rar files were extracted. I have to go into the download folder to delete manually those files, is there possible fix in the work for this?

    Also will you becoming out with a 64bit New Reader? I think there is a market for this. I have been using Xnews New Reader for years, but you can only load 1 to 2 millions articles before it freezes up. I would like 64bit new reader that can download 10 to 20 million articles at a time.



  8. Matt says:


    Yes, that is a bug that will be fixed in the next release.

    I hadn’t considered doing a 64-bit newsreader, but now that you mention it, I will look into it.

    Thanks for the feedback,

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