Microsoft Outlook 2003 has the ability to enable and disable add-ins if it considers them not to be functioning correctly. Unfortunately Microsoft Windows provides methods of sending emails that causes Outlook to think that an add-in is not functioning. The Explorer extension "Send To > Mail Recipient" loads only part of Outlook thus making it think that the add-in has not loaded correctly. This causes Outlook to mark add-ins that have failed to load as "do not load next time" and thus the spamREF Outlook Toolbar disappears.

Luckily it is straight forward to get it back.

In Outlook 2003 select 'Tools' from the Menu bar and then select 'Options'. Select the 'Other' tab and click on the 'Advanced Options...' button on the 'General' tab. Click the 'COM Add-Ins..' button. In the list of available Add-Ins you will see 'spamREF Outlook Toolbar v2'. Simply check the box and click OK all the way out.

The spamREF Outlook Toolbar v2 should now be loaded.

To make sure that this doesn't happen either stop using Send To -> Mail Recipient from Windows Explorer make sure that Outlook is running before you do.

Another possible reason is that you have two copies of Outlook running. If Outlook does not start or shutdown properly it can still be running even though it cannot be seen. In this situation trying to start Outlook again results in two copies running. To check for this problem close down all copies of Outlook that you can see running and then run Task Manager. This is done by right clicking the Taskbar (the bar at the bottom of the screen with the 'Start' menu on it and the clock etc) and selecting 'Task Manager'. When Task Manager loads select the 'Processes' tab to see all the processes that Windows is running and look down the list for Outlook. If it is still running even though you think it shouldn't be then you have found your problem! At this point you can either reboot or kill the rogue Outlook process. To kill the process simply highlight it and press the delete key and accept the warning message. It is possible that when you start Outlook next time it might complain that something went wrong and ask to start in 'Safe Mode' or disable 'Add-ins'. If this is the first time it has happened then say no and see if can correct the problem itself.