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Important bugfix patch for VPOP v6.10 build 2698
Posted by Paul Smith on 16 September 2014 09:38 AM

A significant bug has been found in VPOP3 v6.10 build 2698 which can lead to settings being corrupted. This is triggered by changing any settings on the Settings -> Admin page. (Note that most users do not access this page, so it is unlikely you will be affected by the bug, but it is better to be safe than sorry).

This problem does not affect other versions of VPOP3, only v6.10.

This problem will be fixed in v6.11, but there is also a patch available immediately which can be applied to v6.10. If you have VPOP3’s auto-updates enabled (on Settings -> Misc Settings), then it should install the patch automatically for you, otherwise you can download the fixed ‘utils_admin.html’ file from here, and copy it into the VPOP3\_webmail\admin folder.

If the VPOP3 automatic update has worked, then you should receive an email telling you about the update, but you can check by going into the VPOP3 settings and going to the About page. After the version number it should say “(Patch 160914a)” if the patch has been applied.

You can check whether the bug applies to your installation by going to Settings -> Admin Settings and go to the Message Targets tab. This should show a list of items with drop-down selection boxes. If there is a problem then you will see a very long list of hundreds of items, including strange entries, including \ and ~ characters. In that case, do not press the Submit button on this page, until you have downloaded and installed the patch. If the page has been patched, then you will see a list of 40 or so items, all with more meaningful names.

If you have any questions, please contact

We apologise for any inconvenience.

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VPOP3 v6.9 released
Posted by Paul Smith on 10 July 2014 12:54 PM

We have just released VPOP3 v6.9 which you can download from

This is a free upgrade for all users who have active software maintenance or priority support on 10th July 2014. Other users can purchase the upgrade and 1 year of software maintenance on our website.

The full change log can be viewed in our issue tracker.

Some highlights are:

  • In VPOP3 Enterprise, users can be in multiple groups to allow easier folder sharing
  • In VPOP3 Enterprise, have the option to ‘lock’ folders so they can’t be renamed or deleted (by allow the administrator to set permissions for the folder owner, rather than assuming the owner has full permissions)
  • Changes to the SSL support in VPOP3 to stop problems sending to some other mail servers
  • Allow creating subfolders of ‘Inbox’ in Webmail
  • When changing the archive folder location, move previously archived messages to the new location in the background rather than requiring manual move
  • Fix problem with Add/Edit Alias window in Firefox
  • Add more options for automatic updates of VPOP3 with the aim of reducing the need for manual updates
  • Improvements to the “news” notifications within the VPOP3 settings, to alert administrators to updates/problems they may need to be aware of.
  • Many more bug fixes and improvements (see the change log)

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Background log writer
Posted by Paul Smith on 10 July 2014 12:50 PM

The diagnostic log files which VPOP3 generates can add a lot of extra disk load to a VPOP3 server. For this reason, VPOP3 doesn’t usually write data to the log files as soon as the event happens. The log file entries are held in memory until the “background log file writer” gets around to it, and writes them to the actual disk files. This generally works well, however if the disk is exceptionally slow (e.g. failing disks, or RAID5 SATA drives on a busy system) then it has been known to lead to out-of-memory errors.

The reason that this background writing system is necessary for VPOP3, where other servers may write log files immediately without serious consequences, is because VPOP3 can write to many different log files to make reading them easier. Depending on the settings, it can also write a lot of data to the log files – especially if session logs are enabled. This can cause a lot of disk seek activity, which slows disk access down across the whole PC.

In versions of VPOP3 prior to v6.7, the behaviour of the background log file writer was fixed in the software, but in v6.7, we added configuration options to customize the behaviour. This can be used to decrease disk load further, or to make the log files be refreshed more frequently.


You can customise and monitor the behaviour of the log file writer by going to Settings -> Diagnostics -> Log File Writer

Log Writer Settings

If you turn off ‘Enable logging to file’, then VPOP3 will just discard all logging entries. This is not recommended for normal use, but may be useful as a diagnostic tool to see if performance problems are being caused by VPOP3’s logging.

The settings on this page tell VPOP3 how to change how often to write data to the log files, and how to automatically adjust its behaviour depending on the current load.

VPOP3 writes log file data in ‘bursts’, rather than as the log entries are generated. The main thing you can configure is how long to wait between these bursts. The first 4 settings let you configure this.

Min time between log writer bursts and Max time between log writer bursts set limits for the time between the bursts. In the screenshot above, this means that the delay between bursts can be between 0 and 10 seconds.

The If lines written < X then increase time between bursts and If lines written > y then decrease time between bursts settings tell VPOP3 how to adjust the time depending on load. They mean that if there is lots of data to log, VPOP3 will wait less time between writes, but if there isn’t much data then it will increase the time between the writes, to avoid writing lots of small chunks of data.

The Only write to disk if at least x lines waiting to be written setting prevents VPOP3 writing small bits of data. On a hard disk, each write will probably incur a delay – eg because of disk latency (waiting for the disk to rotate to the correct position) or seek time (moving the write head to the correct track on the disk), so writing small bits of data unnecessarily is not a good idea.

The Always write if oldest line is over x ms old setting prevents stale data sitting in memory for a long time. This overrides the previous setting. For instance, if VPOP3 is just logging errors, it may just generate one log entry every hour – if you had told VPOP3 not to write to disk if there are less than 10 lines to log, there could be a 10 hour delay before the first error is logged, which would not be very helpful, so you can limit the maximum time to delay.

The Current time between log writer bursts value shows how long VPOP3 is currently waiting between bursts of writing to disk.

The Log file stats section shows the current statistics. For instance, how many writes have taken place in the last 10 minutes, and how many lines & bytes were written in that time, and so on. This can help you see if certain log files may be causing a lot of disk access.

The pop3clt.log, smtpclt.log, smtpsvr.log, smtpclt.log, imapsvr.log, nntpsvr.log, nntpclt.log files are Session Logs which can be enabled/disabled on the Session Logs tab. If you have lots of writes to the VPOP3.log file, you may want to decrease the logging level on the General tab.


An advanced, but very effective way of decreasing disk load is to set up a RAM disk (e.g. and have VPOP3 write its log files to that. Since you will rarely want to access diagnostic log files after a computer reboot, this works well. If you have a RAM disk, then you can change the background log file writer configuration so that it writes to the log files more frequently, as disk seek times are not an issue.

Using an SSD for log files is not recommended. It will work fine, but SSDs have limited write cycles, so using them for write-heavy tasks such as log files will reduce the lifetime of the SSD.

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Free Webinars / online training
Posted by Paul Smith on 08 July 2014 12:28 PM

We are planning on holding some Webinars /online training events for VPOP3 users and partners. These will be free, but availability is limited.

The initial planned dates are:

Friday 29th August 3.00pm – 4.00pm – beginners (registration)

Friday 12th September 3.00pm – 4.00pm – advanced usage (registration)

Friday 19th September 3.00pm – 4.00pm – beginners

(The above times are UK time – UTC + 1hr)

Please email if you are interested, indicating the session you would like to ‘attend’.

Rather than being a carefully choreographed “isn’t our software great” presentation, we plan to make it more of a Q & A session. If you can give us advanced warning of any questions you may have, this would help as we may be able to set up our demo machine accordingly to avoid wasting time during the session. If there aren’t specific questions, then we can run through some things, but if you have questions, it may be more helpful to use those ideas. Note that we cannot guarantee to answer all questions – we have to consider whether they may be appropriate for the session in question and may be helpful to other attendees.

(Note that this is a new venture, so there may be teething troubles initially – please bear with us in that case).

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Reduced technical support availability
Posted by Paul Smith on 08 July 2014 12:17 PM

From 23rd until 27th October (inclusive) there will be reduced technical support availability due to staff holidays. We recommend that you do not plan to do any routine work to your VPOP3 servers during these times (eg server migrations, upgrades etc).

We request you send your support requests through our web support portal at during this time if possible. In an emergency (ie a server down situation), you can call, but there may still be delays in replying, so email is often better in any case.

Note that our knowledgebase has lots of useful information on it, including troubleshooting tips if VPOP3 or VPOP3DB (PostgreSQL) won’t start. Most of the questions we get asked are already answered in our knowledgebase.

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VPOP3 Antivirus v1.0.8 released
Posted by Paul Smith on 02 July 2014 03:22 PM

We have just released VPOP3 Antivirus v1.0.8 which you can download from here.

This version fixes a problem with v1.0.7 which could lead to excessive CPU usage if the virus scanner was idle for too long. 1.0.7 was released to fix a problem with updates not succeeding for some people.

To install it:

  1. download the installer
  2. Stop the VPOP3 service
  3. Run the installer
  4. Restart the VPOP3 service

If you have VPOP3 v6.1 or later, with the automatic update facility enabled, then it should have downloaded the later version, but you will need to restart the VPOP3 service for it to take effect.

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