Hi Sven.

Thanks for your reply.

Here is our log4net.config we use for this webapplication. Some names are changed for security reasons. :)

<?xml version="1.0"?>
<log4net>

  <root>
    <priority value="Info"/>
    <appender-ref ref="AsynchronousLog4NetAppender" />
  </root>

  <appender name="rollingFile" type="log4net.Appender.RollingFileAppender">
    <file type="log4net.Util.PatternString" value="App_Data\Logs\UmbracoTraceLog.%property{log4net:HostName}.txt" />
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <appendToFile value="true" />
    <rollingStyle value="Date" />
    <maximumFileSize value="5MB" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value=" %date [P%property{processId}/D%property{appDomainId}/T%thread] %-5level %logger - %message%newline" />
    </layout>
    <encoding value="utf-8" />
  </appender>

  <appender name="AsynchronousLog4NetAppender" type="Umbraco.Core.Logging.ParallelForwardingAppender,Umbraco.Core">
    <appender-ref ref="rollingFile" />
  </appender>

  <appender name="OurAppender" type="Umbraco.Core.Logging.AsynchronousRollingFileAppender, Umbraco.Core">
    <file value="App_Data\Logs\OurTraceLog.txt" />
    <lockingModel type="log4net.Appender.FileAppender+MinimalLock" />
    <appendToFile value="true" />
    <rollingStyle value="Date" />
    <maximumFileSize value="5MB" />
    <layout type="log4net.Layout.PatternLayout">
      <conversionPattern value="%date [%thread] %-5level %logger - %message%newline" />
    </layout>
    <encoding value="utf-8" />
  </appender>

  <!--Here you can change the way logging works for certain namespaces  -->

  <logger name="NHibernate">
    <level value="WARN" />
  </logger>
  <logger name="NHibernate.SQL">
    <level value="ERROR"/>
  </logger>
  <logger name="Raven">
    <level value="ERROR"/>
  </logger>

  <logger name="our.helper">
    <level value="INFO" />
    <level value="ERROR" />
    <level value="DEBUG" />
    <appender-ref ref="OurAppender" />
  </logger>

  <logger name="our.customers.webapplication">
    <level value="INFO" />
    <level value="ERROR" />
    <level value="DEBUG" />
    <appender-ref ref="OurAppender" />
  </logger>
</log4net>

We use this in a lot of projects and only one has this error.

After some search the explanation might be that an earlier error prevent log4net access to write about the error occurring.

But i get back when i know more.

Hi ewuski.

To be honest, i can't even remember what project this was on.

And i cannot remember if we got it solved. My guess is that we did not got it solved, because i tend to report back my findings :)

Ok, thanks for replying anyway