Network Problems

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How to determine your upload speed[edit]

To configure Vuze for optimum performance, you need to know the upstream capacity of your Internet connection, which can be obtained from your Internet Service Provider (ISP). Advertisements may include numbers like "1024/256 Kbps"; this represents the maximum bandwidth available to you. It is the number of kilobits per second (kbit/s or Kbps) you can download/upload with your connection. You may have seen speed measured in kilobytes per second as commonly reported by browsers. There is a difference between the two measures. In all likelihood, you upload slower than you download.

You may visit or for online speed tests. Stop ALL Internet activity on your machine (including torrents) for a few minutes before running a test. Repeat it twice to reduce number anomalies.

You can always set Config > Transfer > kB/s global max. upload speed to 0 -- meaning unlimited -- and observe. In any case, do not let Vuze (or any other program for that matter) take up the whole upload bandwidth. There needs to be room for overhead such as acknowledgement signals (ACKs) and resend requests. Downloads will suffer if these signals cannot be sent. Set your upload limit to about 80% of the maximum possible.

How do I setup Vuze to download faster?[edit]

First is to make sure that you have setup your ports in Vuze properly especially if you are behind a firewall or router. You'll need to add an exception for Azureus.exe (the main Azureus process) to your Software firewall (Windows)]. If you are using a Mac, check your firewall settings under (System Preferences > Network). And it is necessary to forward Azureus' TCP and UDP listening port (see Tools -> Options -> Connection) from your router to your PC, there are 2 ways to do that:

When your Router supports UPnP you may want to enable it in the router configuration and in Vuze (Tools > Option > Plugins > UPnP) If UPnP isn't supported or doesn't work correctly you have to do manual Port forwarding.

Downloading as fast as your connection allows requires good settings based on the upload speed of your Internet connection. First, fix your NAT problem if you never see and do not Force Start your torrents. Running another P2P program while Vuze is running will stall your downloads badly.

NOTE: Make sure to check out: Bad Routers and Bad ISP's

How do I setup Port forwarding on my router?[edit]

To be able to setup rules to forward Vuze listening ports (UDP and TCP) as external port to the IP of your computer and the same port on your computer, visit for more info.

Note: first find out the brand and exact version of your router, then select the router from the Routers page, skip over the advertisement page and then select Vuze on the application, and then you should arrive at the settings page.

What do I do if I have Firewall software?[edit]

Just like the wide array of routers available to consumers, so too is the list of software firewalls, and each has different features and capabilities. Because of this huge variance, we will again attempt to approach this as broadly as possible. A software firewall can offer the same protection that a router can and it can mimic the symptoms of a NAT error. So why should you use both? A router can only protect you from incoming data on certain ports - a good software firewall can monitor outbound traffic too. Consider this an added layer of security.

If you use a software firewall on their PC, the following information applies to everyone who hopes to fix their NAT error.

You should never have more than one software firewall installed and in use at any given time (analogy: two drivers wanting control of a steering wheel).

In order for Vuze to run correctly, access/permission must be allowed.

  - If your software firewall has options for a security level, reduce it from "high" to "medium" if it isn't already there. 
  - Your software firewall must allow "Azureus.exe" access/permission.

Note: For further detailed information about Firewalling click here.

Having problems with UPnP?[edit]

UPnP troubleshooting steps

Why do I lose Internet connectivity after a while?[edit]

The problem is most likely related to your router. Click here for more information.

Why are most of my torrents queued and not downloading?[edit]

On Windows:

Go to Tools > Options > Queue > Max simultaneous downloads and Max active torrents.

On Mac OSX:

Vuze > Preferences > Queue > Max simultaneous downloads and Max active torrents.

These numbers determine how many torrents run simultaneously. Do NOT change them before reading Good settings! Otherwise, you may see your download speed DETERIORATE. Make sure you are downloading good torrents, too.

The Max simultaneous downloads is the maximum number of torrents downloading at any moment.

The Max active torrents is the maximum number of torrents you download or seed at the same time.

Note: If you are downloading torrents from a third-party site, it's possible that the tracker is overloaded with requests and the client does not receive a response back from the tracker in the required amount of time. From the Advanced screen, try going to the details page of the torrent and see if the trackers are online. Click the tracker URL, your browser should open up and should pull up a page. Also try downloading content from Vuze and see if you would experience the same issue.

Why is downloaded/total size not equal to completion percentage?[edit]


Total size - Size of the data to download.

Downloaded - Size of the data already downloaded.

Done - Percentage of the data verified and written to disk.


Vuze downloads piece by piece, and multiple pieces at a time, so at a given moment, more has been downloaded than has been verified, so you will always have a "done" percentage less than the downloaded vs. total size percentage.

On slow downloads, you will most likely download pieces twice (if it's slow, you request it from multiple peers hoping to get it faster but you will get it more than once as well).

If Vuze happens to crash ( very rare ;) ) the data downloaded will be counted but all the unfinished pieces will have to be re-downloaded on restart and that will again amplify the difference between the two.


8MB file made of two 4MB pieces. You have downloaded one piece completely and have 2MB out of the second piece.

You have downloaded and verified one 4MB piece, out of 8MB to download, so your "done" percentage is 50%. But you have actually downloaded 6MB out of 8MB so you are 75% complete. But we don't include that in the "done" count because we don't know if the piece will pass the validation.

What do I do if my network connection keeps dying?[edit]

Vuze (and BitTorrent clients in general) place a great deal of stress on the networking system - particularly network card drivers, and router/modem firmware - which can cause them (and/or the OS) to crash or lock up under load. I would suggest looking to see if there are newer drivers/firmware available for your hardware, or replace the buggy things completely.

However, there are a few things you can try to help alleviate the problem:

? Limit the Maximum number of connections per torrent in Vuze > Tools > Options > Transfer to 40 or less, as well as limit Maximum number of connections globally to 100 or less.

? Reduce the Max simultaneous outbound connection attempts rate to 1 or 2 in Vuze > Tools > Options > Connection.

Note: If you are running Zone Alarm (version 5 in particular), you might try disabling or uninstalling it and rebooting. Many users have reported problems with ZA breaking BitTorrent clients.

Additional note: As a general rule, a lot of home-routers can only handle a total number of 255 connections open at any one time. Thus, if you have many machines running on one network, your router will quite likely occasionally either lock up / crash or randomly dump connections it decides it can't handle (depending on how well the firmware is written). Your only solution really is the above: reduce the number of possible connections (unless you can afford to shell out on an expensive corporate router that is!)

If it's your router that is dying and not your network card have a look at the bad routers page.

Why am I seeing a yellow bar every time I click on the 'Play or Download' link in Vuze?[edit]

This normally happens when your are using other browsers in Windows OS (i.e. Safari, Opera or Firefox). There are some issues with the Opera and Safari 3 (Windows Public Beta) browsers not associating the Java Web Start when clicking on the download link.

Note: This normally happens when the Vuze client is not running.

Opera Browser

Here is a work around to teach Opera to hand off *.jnlp files it finds to Java Web Start, javaws.exe.:

   1. Click (Tools > Preferences > Advanced Tab)
   2. Click on the 'Downloads' menu on the left window.
   3. Check to see if an association for "jnlp" is already there.
   4. If there is no entry, Click "Add"
   5. If there is one already, select it and Click edit.
   6. The MIME type should read "application/x-java-jnlp-file", the file extension should read "jnlp" and "Open with default application" should be selected.
   7. Click OK.
   8. Click OK to close the Preferences window.    
   Mac OSX    
   1. Click (Opera > Preferences > Advanced Tab)
   2. Click on the 'Downloads' menu on the left window.
   3. Check to see if an association for "jnlp" is already there.
   4. If there is no entry, Click "Add"
   5. If there is one already, select it and Click edit.
   6. The MIME type should read "application/x-java-jnlp-file", the file extension should read "jnlp" and "Open with default application" should be selected.
   7. Click OK.
   8. Click OK to close the Preferences window. 

Safari 3 (Windows Public BETA)

Download the latest version available. If it still does not work, we suggest using a different browser instead.

Note: This is just a work around, but in doing these steps and you still experience some problems, the best solution is to browse content from the Vuze client and not from your browser.

The Internet gets slow when Vuze is active[edit]

If web browsing or e-mail usage seems slow while Vuze is active, or Vuze's speed constantly fluctuates going up and down, you may try to correct that by limiting Vuze's speed.

In general, Vuze uses as much internet bandwidth that you let it have. It downloads and uploads as fast as possible. In practice, most users have asymmetric ADSL or cable modem connection (like 1024/256kbit or 10/1MBit), where the upload is the critical factor, as it is much smaller that download bandwidth from your ISP. If Vuze takes over all your upload bandwidth, then even the web browsing gets slow as even your outgoing requests for web pages get slowed down. It also slows down your Vuze downloads, as data arrival messages and requests for new data also get stuck in the outgoing packet queue.

In most cases, you should not limit the download speed. You may limit it somewhat to leave room for web browsing etc., but in general the upload bandwidth is the one you should pay attention to.

The easiest way to try to correct "slow internet" is to go to Vuze's Transfer options and set the "global max upload speed" to 5-10 kB/s less than your max. upload bandwidth. (And please understand, that ISPs use kilobits/megabits, while Vuze uses kiloBytes by default. 1 Byte = 8 bits, 1 kB/s = 8 kbit/s = 8 kb/s. Small and capital 'B's do matter.) Pretty good simple thumb rule is to divide the ISP kbit/s speed by 10 and you arrive at rather suitable kByte/s speed for Vuze. For example, an ADSL with 700 kbit/s upload bandwidth, which corresponds to maybe about 70 kB/s as effective upload capability --> set max. global upload to 65-70 kB/s. That will leave enough bandwidth for web browsing and e-mails. Examples of reasonable settings can be found here: Good settings

After setting the max. speed, the more advanced way is to Use the *built-in auto-speed* functionality. That will sniff your internet connection speed and other usage and will manage the bandwidth that Vuze uses. The basic idea is to prevent Vuze from choking your upload bandwidth with too much traffic, but still try to upload as much as possible.

You can find it in: Tools/Options --> Transfer --> Auto-speed.

You can set it to be active for downloading and seeding and then select either "Classic" or "beta" mode.

I personally prefer the autospeed "Classic" mode, as it can be tinkered to more detail. If you use Auto-speed classic, please remember to also set the max upload speed in its settings. (The "choking ping time" is the most important tinkering parameter there. It tells the autospeed, how well you want the connection to respond. I have it at 150 ms and decrease step at 13 kB/s to have aggressive speed reduction, if needed.)

My settings for Auto-Speed Classic with 1 Mbit/s upload bandwidth in my internet connection: Vuze4310OptionTransferAutospeedClassic.PNG

Note: one possible reason for Vuze transfers stopping and web browsing slowing, is that you have too many connections, which confuses your router/modem. One symptom is that your modem/router reboots itself, or you need to unplug it for rebooting. You might try to limit "Max. connections globally" (in Transfer options) to 200 or less, especially if you have one of these routers: Bad_routers

Note: one additional possible reason is the built-in (security) limit for "half-open" connections built-in Windows TCPIP.SYS drivers since XP SP2 (included in XP SP3, Vista and Windows7 versions). If that is the reason, your Windows Event log contains errors with Event ID 4226 ( ). The effect of the limitation can be mitigated by lowering the pace with which Vuze tries to open new connection in boot-up phase. Set the option "Max simultaneous outbound connection attempts" to 10 or less in Vuze's Advanced Network Settings. There are also 3rd-party patches for TCPIP.SYS drivers, which remove the limits, but you use the patches at your own risk.

Please note, that many useful options discussed here are not shown in the "Beginner" mode. You have to first set your user proficiency to "Intermediate" (or Advanced") in Mode page of Options.

Why am I experiencing failed updates?[edit]

Installation of at least one component failed in your config directory there will be an "update.log" file which contains technical logs on the component update. The newest update is at the bottom of the file, starting with the line "Update Starts:". The typical reason for a failure is that you do not have rights to write to folders required for the update.

Note: If the log is of no help to you, you can always send a to support via (Help >Generate Debug Info). The will contain the update.log. When e-mailing, please indicate that this was a update failure so we know where to look :)

________________________________________ Windows Vista users ________________________________________

Check on your UAC (User Access Control), this could be preventing you to install updates on your computer. You can try logging in as the Administrator, give write access to directories specified in the "update.log" file and follow the steps below:

Step 1: Open an Administrator Explorer window

  1. Click Start
  2. Type: explorer
  3. Right-click Windows Explorer
  4. Click Run As Administrator

Step 2: Change security settings

  1. Find the folder you need access to from the Administrator Explorer window
  2. Right-click it
  3. Click Properties
  4. Click the Security Tab
  5. Click Edit
  6. Click Add
  7. If you are the only one that needs modify access to this file, type your username and press enter. Otherwise, type "Users" and press enter.
  8. Click the checkbox under Allow next to Full Control
  9. Click OK
 10. Click OK

Note: You will need to repeat Step 2 for every folder that you need modify access to.

This will open an "Administrator" explorer window. Every action that you take from this window will be executed with full Administrator permissions.

If you are still experiencing issues, you can try turning off the UAC. However, Microsoft strongly recommends that you do not disable User Account Control. So to turn UAC off, follow these simple steps:

  1. Click Start
  2. Click Control Panel
  3. Click User Accounts and Family Safety
  4. Click User Accounts
  5. Click Turn User Account Control On or Off
  6. Uncheck the checkbox
  7. Click OK

Note: You will need to restart your computer for the change to take effect. This change affects all accounts on the computer, not just yours.

________________________________________ Mac OSX users ________________________________________

If you get an error indicating that, for example, "/Volumes/Vuze/" isn't writable then you are running Vuze from the wrong location. You need to stop Vuze, move into "/Applications" and then restart it from that location.+

________________________________________ Linux/Unix notes ________________________________________

If you installed Version or higher, you can also try a manual update.

     1.	Make sure Vuze is not running 
     2.	Open up a shell 
     3.	Change to the azureus program dir 
     4.	Run "./updateAzureus" (If this is your first time using the script, you may have to "chmod +x ./updateAzureus"). If you don't have this script, you can create one:
               sudo java -cp ./plugins/azupdater/Updater.jar org.gudy.azureus2.update.Updater updateonly `pwd` ~/.azureus

Assuming you have a ./plugins/azupdater/Updater.jar, this will elevate your rights and apply any updates that couldn't be done with your normal user's rights.

I am getting a "Disk read error" message when trying to download content, what do I do?[edit]

There are some users who are downloading content and the download goes into that state. Make sure to clear up some space on your hard drive, either by deleting unused files or by clearing up your recycle bin. After you have made enough space on the drive, go back to the Dashboard tab and click on the 'Resume' button.

If you are still receiving errors after freeing up some space on your drive, try doing the following:

   1) Go to the Advanced section of Vuze (View > Advanced > My Torrents) to open your Torrent window.
   2) Highlight on the torrent that has the error.
   3) Click on the Stop button
   4) Right-click on the torrent and choose 'Force Re-check'.
   5) Then click on the Play button to resume download

It is also possible that an application is trying to access the same file, maybe an indexing service like Google Desktop, etc. Stop the application that is trying to access the Download directly or tell it to skip your download directory. To figure out which application does that use FileMon from Microsoft Sysinternals. To restart a torrent that has this error, just stop the torrent and the click on "queue" again.

I get green smilies but my downloads are still slow[edit]

If you get green smileys HealthOk.gif as torrents' "Health", then you know that your basic network settings are ok. However, that doesn't guarantee speedy transfers.

It is good to understand that

  • there is no central server from which you download. Everything that users download, is at the same time uploaded by users
  • you contact other users for your downloads
  • respectively, others should be able to contact you (NAT & port forwarding to be configured)

It is quite possible with a "new" torrent or an one with "small" swarm (only a few peers), that the missing pieces are not available. So, it is quite possible that torrent remains active with "downloading" status, but is not actively downloading anything as there is nobody to download from.

The low speed or inactivity may also be due to low amount of seeds/peers in the torrent, or their slow upload capability. As there is no central server, your download speed is directly dependent on uploads from others. The torrent's downloaders' total download speed matches the total upload speed.

You can monitor individual torrent's status very well by opening the details for that torrent: UG_Advanced_Information#General_tab

Vuze contains dozens of data items which will help you to understand why a torrent is slow, or why it doesn't progress. The same fields can also be seen in "My torrents" and "Detailed list". You can rather freely select the fields shown by using the Column setup dialog. (For some mystery reason, some of the most useful fields require "Intermediate" or "Advanced" user mode, which you can change in Options / Mode.)

Some key fields for torrent status:

  • Done: your own download completetion percentage
  • Availability: tells you how many full copies you see right now. If Availability is below 1.0, you don't see a full copy now and can't complete the download now. In new swarms, there is only the original uploader and others start empty. Thus the Availability may be over 1.0, but in reality most peers have only a few percents completed. This may lead to slow downloads. For example, if you are connected to 1 seed and 88 peers, your Done is 30% and Availability is 1.32 (132%), then in practise only the original seeder has full 100% copy, and the others (you included) have 32% of data. As you already had 30%, the other peers only have 2 more percents of data for you to download.
  • Swarm average speed: tells you how quickly others are downloading on average. Individual speeds depend on bandwidth (and luck), but the average is roughly what you should expect to reach yourself.
  • ETA: Estimated Time of Arrival. Fluctuates, but tells you a rather realistic forecast of remaining download time.

A picture of my Vuze shows typical situations with torrents and that the speed vary a lot by individual torrents: Vuze42Availability.png

  • Torrent 1 is 62% Done, but has only .640 availability, so not much to download from. 0(1) Seeds, 33(97) peers. I have no contact with the single seed, who is the only one with the remaining 36%. Download speed has dropped to less than 1 kB/s. The remaining download time (ETA) is over 21 days.
  • Torrent 2 is 52% Done, and has availability of 1.539. So, I have contact with the single seed (1.), but *the others are (.539) roughly where I am* (.524), so the speed is currently only 10 kB/s as most of the missing parts are available only from the single seed. ETA is 10 hours.
  • Torrent 3 is 20% Done, and availability is 37.989, so there is abundance of seeds and the download speed is 493 kB/s. ETA is only 7 min.

More examples can be found in the Availability article.

In general, many bittorrent client implementation reward good uploaders when selecting data transfer partners, so your upload speed has impact on your download speed. So, having more upload speed in your ADSL/cable connection will also speed your downloads.

Please also understand, that ISPs typically use kilobits/megabits, while Vuze uses kiloBytes by default. 1 Byte = 8 bits, 1 kB/s = 8 kbit/s = 8 kb/s. Small and capital 'B's do matter. If your ISP has promised you a 500 kbit/s connection, you could thus expect max. 62 kB/s downloads...

The downloaded files can be really big. So the download can easily take hours or days with the biggest files.

Traffic shaping: Your ISP may also monitor and throttle bittorrent traffic. Check the Bad ISPs list. If you think you might be blocked/throttled/shaped, you might consider encrypting Vuze traffic: Avoid_traffic_shaping

Please note, that many useful options discussed here are not shown in Vuze's "Beginner" mode. You have to first set your user proficiency to "Intermediate" (or Advanced") in Mode page of Options.