How do I eliminate duplicate logging in log4net?

You are getting duplicated because you are telling it to log messages twice. I wouldn’t recommend using additivity here since you might experience some side effects, simply remove unnecessary configuration:

<root>
    <level value="WARN" />
    <appender-ref ref="Console" />
    <appender-ref ref="LogFile" />
</root>
<logger name="myprogram">
    <level value="INFO" />
</logger>

You don’t need to indicate the appender-ref in the logger myprogram since it will inherit them from the root logger; if you specify them again it will log twice.