Installing or upgrading MailFlow Monitor

First ensure that you have downloaded the latest version from the Downloads section. If you are upgrading from an older version then it is strongly recommended that you uninstall the old version first. See instructions later in this section if you need to do this.

Launch the setup program and proceed as you see fit. You are welcome to change the installation folder if you wish, but it’s fairly small in size. MailFlow Monitor doesn’t need to setup a database or create cache files so it’s not going to take up a large amount of room on your installation drive. A typical installation takes up a few hundred KB in the installation folder, and then a few hundred KB to a few MB in the logfile folder (more on this later).

Once installed you can launch the main application by double-clicking the new shortcut on the desktop or by clicking on Start > Programs > FruitWorks > MailFlow Monitor > MailFlow Monitor. You will be presented with the window shown below:

MailFlow Monitor – main window

MailFlow Monitor will run through a few checks and as part of this it will look to see whether its Exchange Transport Agent is registered. The Agent is responsible for parsing the email headers as they enter and leave the Exchange server – and this is how MailFlow Monitor is able to present a summary of your mail flow in the main application window. If this is a brand new installation you’ll shortly be presented with the screenshot below – alerting you to the fact that we need to install the accompanying Exchange Transport Agent.

MailFlow Monitor – Agent Installation warning

Installing the Exchange Transport Agent is very simple. Just go to Tools > Agent Options > Install Agent as shown below.

MailFlow Monitor – installing the Monitoring Agent

MailFlow Monitor will now install its Exchange Transport Agent and register it with Microsoft Exchange. This whole process requires a few restarts of the Microsoft Exchange Transport service so it can take a minute or so, and do bear in mind that this may temporarily cause your Outlook clients to drop their connection to the Exchange server. If all goes well you’ll shortly be presented with the following message.

MailFlow Monitor – Agent installation success message

That’s it! The application is now installed and running. You can verify this by sending an email from an external account (eg your personal email) into your organisation. You should see it appear in real time in the main application window. You can then reply to that email and you should see your reply appear in the windows as well. As more emails appear, the application window will automatically scroll to show the most recent email at the bottom.

Queue Overview

At the bottom of the main application window you’ll see an overview of the Exchange server’s queue status. This is split into two values: Queue and Poison. Queue is the total number of messages in all queues – normally these are messages waiting to leave your organisation. It’s normal for this to be something other than zero if you have a busy Exchange server. Poison is the total number of messages in the Poison queue. If this is anything other than zero then the line will be coloured red to draw it to your attention. At this point you should investigate your Exchange server further as Poison messages will never be automatically reprocessed by Exchange – they will sit in that queue indefinitely (not giving a warning or bounce back to the sender) until you take further action. More information on the Posion queue is available in the following TechNet article:

Application Options

There are a limited number of options available to select within the main application window. You’ll find these under Tools > Application Options

Use Local Time

This will query your system’s regional settings and use the same offset when displaying each message’s Date & Time in the application window. This is disabled by default, in which case the Date & Time will be UTC.

Clear Application Log at Startup

This clears the application log at startup (see below) and will prevent the application log file growing indefinitely over time. This is disabled by default but if you ever need to troubleshoot the application then it’s really only the most recent entries that will be helpful, so it often makes sense to enable this.

Reviewing the log files

MailFlow Monitor keeps a log of its activity in C:\ProgramData\FruitWorks\MailFlow Monitor. You can open these directly by browsing to them in Windows Explorer or you can select them through Tools > View Logs > Application Log or SMTP Log.


This is a log of activity performed by the main application, and is useful when troubleshooting agent installation or uninstallation problems. If you ever need to contact FruitWorks for support then we’ll likely ask for a copy of this log as part of the troubleshooting process.


This is a log of all SMTP activity as recorded by the MailFlow Monitor Transport Agent. This is a CSV-formatted logfile and can be useful for your own analysis or if you want to keep a long-term record of all SMTP traffic.

Uninstalling MailFlow Monitor

Uninstallation is a simple process, but it is important to first uninstall the MailFlow Monitor agent before uninstalling the application. This is because without the application you will have no way to uninstall the Transport agents without resorting to the Exchange Management Shell!

As with the installation process, this will restart the Microsoft Exchange Transport Service at least twice, so you might like to do this at a quiet time of day.

Launch the MailFlow Monitor application and go to Tools > Agent Options > Uninstall Agent. If all goes well then you should see the screen below:

MailFlow Monitor – Uninstalling the Monitoring Agents

You can now close the application and proceed to uninstall it just as you would any other Windows application via Control Panel > Programs and Features.


MailFlow Monitor is provided without any warranty or guarantee as detailed here but I always welcome feedback – whether it’s to tell me that you’re making good use of the product, to request a new feature, or to report a bug (surely not!). Please visit the Contact page to send me a message.

IMPORTANT: Rather than relying on the Agent version detection and upgrade processes it is strongly recommended that you use your currently installed version to uninstall the Agent and then uninstall the Application itself from Control Panel > Programs and Features. At that point it would also be a good idea to reboot your Exchange server to ensure it releases the lock on the MailFlowMonitorAgent.dll in the Exchange program folder.

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