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Outlook™ Synchronization

For general Outlook configuration click here...




Synchronization of Calendars and Contacts

Mailtraq provides two synchronization services for Outlook (32-bit):


These sync services have been tested through Outlook 2013.
Structural changes to Outlook 2016 may affect the behavior of the sync tools and restrict their effectiveness.


MOS - Mailtraq Outlook Synchronizer for LAN (local network) users

MOS provides MAPI connectivity between the user and calendar and contacts held on the Mailtraq server.

MOS gives the best Outlook multiple synching options but is only available for LAN users

Read about installing and using MOS below


Using other synchronization services (NOT supported)

You may use MOS or SyncML services on the Mailtraq server at the same time, but each user may use only one or the other service - do not use both MOS and SyncML on the same mailbox. The two services flag synch data in conflicting ways.


Read ahead
We recommend reading about 'Working with Contacts & Address Books' before you start syncing. That section gives advice on how contacts and address books work in Mailtraq, and the importance of Administrator status for populating and maintaining the Global  Address Book.


MOS - Local Area Network (LAN) Synchronization

These sync services have been tested through Outlook 2013.
Structural changes to Outlook 2016 may affect the behavior of the sync tools and restrict their effectiveness.

How to set up Contact and Calendar sharing between Outlook™ users on your local network using Mailtraq Outlook Synchronizer (MOS) as the MAPI client. 


Mailtraq Professional provides each user with a Calendar and a Contacts directory (viewed in Mailtraq WebMail). MOS connects each individual user's Outlook to this central calendar and contact resource and allows Users to synchronize their own Calendar and Contact list with the main resource held in Mailtraq.

Users can then share Calendar and Contact information with colleagues.

Mobile device users can then synchronize with their desktop Outlooks in the normal way, and so be synchronized with the Organization's Contacts and Calendar.

Configuration Tip:
Read about 'Working with Contacts & Address Books' before you start syncing.

Backup before you start
As with any form of synchronization, you should always backup your existing data stores (Outlook and Mailtraq) before the first sync event.



MOS must be installed on each User's computer and needs to have the MOS service running in Mailtraq itself.
MOS is available from Mailtraq 2.11 (
find out about Upgrading older Mailtraqs here).

Step 1.

Make sure the MOS service is running.
In the Mailtraq Console select Active Connections/Services in the left-pane, and check that Mailtraq is showing a connection for 'MOS - Mailtraq Outlook Synchronizer. If it is not, then you need to add the service from the Options | Services dialog. You may also need to adjust your firewall settings to allow traffic on Port 7888

Step 2.

Install the MOS MAPI client on each User's computer

MOS is part of the standard package as an optional 'Custom' component. it will install into the 'Mailtraq Folder' - the default location is 'C:\Program Files\Mailtraq'
See how to install below ...


Step 3.

Configure the MOS client to synchronize the Outlook 'folders' for Contact and Calendars with the desired Mailtraq 'folders', and select an appropriate Schedule.

Select the desired combination and use the button to 'Link to ..' or 'Unlink ...'

The button toggles state depending on the selected configuration.

1 - MOS doesn't delete anything in Outlook. 
It moves the items to the Deleted folder and that can be easily
undone in Outlook by moving them back.

2 - It is always good practice to backup your Outlook data files before making changes to configurations.

3 - You cannot use both mobile SyncML and LAN MOS on the same mailbox - you must choose one method or the other as they flag data in conflicting ways.


Client install

MOS is included with your main download, and should be selected during installation by choosing the 'Custom' option, in addition to any other options.

MOS is a 32-bit application and cannot connect to a 64-bit version of Outlook.

No matter where you install Office, the 32-bit version of Outlook is always recommended.
Outlook requires the use of MOS build 3574 or above.


Client machines
When you are installing MOS on a client machine, then you should run the installer and at the Custom Setup option select only the 'Mailtraq Outlook Synchronizer' as shown below.


If you have previously installed Mailtraq you may access this dialog by going to the Control Panel, Programs and Features, find "Mailtraq Server" and select the  "Modify" or "Change" command.

Troubleshooting installation
If after you have 'installed' MOS on a client machine you get an error message similar to:

Unable to log on to Outlook: Invalid class string, ProgID:
"MailtraqOutlook.RDOSession" -- Please ensure that Outlook is properly

then either you are not logged onto the client machine with sufficient Administrator rights when running the MOS Installer or you may have some Registry write-protection (anti-virus) enabled on the client machine that prevents the Installer from writing to the Registry.

You need to adjust the anti-virus software permissions to allow the Installer to work.

Update your MOS

If you still have a problem then you can replace the shipped MOS.exe

Install MOS on the remote machine (the one with Outlook installed on it) as described above:

That will place a file called MOS.exe in this folder.
C:\Program Files (x86)\Mailtraq

Delete that file and replace it with the one in this download:  MOS3574
(Download and extract)

And then reboot.


If you still have a problem try to register the DLL manually:

Manual registration 

Having run the Installer it should have put (by default) the MailtraqOutlook.dll into:
C:\Program Files\Mailtraq   or   C:\Program Files (x86)\Mailtraq

Locate the MailtraqOutlook.dll on the machine in question.

Then, in a Command window, from that location,

cd "C:\Program Files\Mailtraq"

cd "C:\Program Files (x86)\Mailtraq"


Regsvr32 MailtraqOutlook.dll

That should manually register the DLL.
And then reboot.

Manually edit the Registry

If that fails you may be able to manually adjust the Registry entries as described below. You should take a backup of your Registry settings before manually editing the Registry.

Adjusting the Registry on the client (users) computer
In the Registry from the account with the problem there should be a key:


   With a subkey Clsid that has a default value (as shown in the image below) of


And there also should be a Registry entry:


...which should have a default value with the path of the MOS DLL.


Troubleshooting notes

Set-up data
The set-up data for MOS is stored here by default: 

C:\Documents and Settings\<user>\Application Data\MOS

This file is not removed if MOS is uninstalled.

Log file location
Detailed logging can be enabled in MOS at the Help menu item.

Log files are stored in the \Mailtraq folder in older versions of Windows. In more recent versions it is at:


MOS deleted my ....

MOS doesn't actually delete entries, it just moves them to the "Deleted Items" folder where it is pretty easy to drag them back.  If they aren't in there, then it wasn't MOS.

Migrating from the previous Mailtraq Assistant*

Note: MOS is not an upgrade to MA and as such it is not aware of any previous synchronizations that have been performed. This is important because if you have previously synchronized then when you first synch with MOS it will duplicate all objects in both your Outlook folder and the Mailtraq folder.

If you are going to perform an upgrade then you should either empty (delete, rename, move, whichever best suits you) either the Mailtraq folder or your Outlook folder before starting. Your choice of whether to start with an empty Mailtraq or Outlook folder should depend on which contains the most complete information. MOS, like MA, doesn't synchronize every property, just those that are relevant to Mailtraq. So if you originally created the entries in Outlook then you should empty Mailtraq's folder. If you created the entries in WebMail, your should empty the Outlook folder.

*Mailtraq Assistant
MA provides instant messaging and desktop mail notification services. Prior to Mailtraq 2.11 MA also provided an Outlook synchronization service. This has been replaced by MOS and in due course the synchronization features of MA will be withdrawn.


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