That is correct: most likely there is a 3rd party program running in background that needs to keep Outlook running as a process. For example, ActiveSync needs outlook.exe running, even if you exit the Outlook interface. When you restart Outlook, it will resume over the already running process, without loading the add-ins (including Easy Mail Merge). The only solution is to close/kill that outlook.exe process and do a clean Outlook restart.
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