Dennis, The error seems new to me, because I had encountered lot of issues while implementing the log4Net in my app.
Please check the below option , it might help you.. 1.In your web.config enable the log4net enable <add key="log4net.Internal.Debug" value="true"/> After </system.web> <system.diagnostics> <trace autoflush="true"> <listeners> <add name="textWriterTraceListener" type="System.Diagnostics.TextWriterTraceListener" initializeData="c:\\logerror.log" /> </listeners> </trace> </system.diagnostics> 2. <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net,Version=1.2.11.0, Culture=neutral, PublicKeyToken=669e0ddf0bb1aa2a"/> </configSections> 3.In you config ,is this the full path <file value="logfile.txt" /> make sure you have full write permission. 4.I was using EventLog appender , so I gave permission to create the log for the users. 5.mention using log4net; using log4net.Config; using System.Reflection; using System.Diagnostics.Eventing; 6.try public static readonly ILog log = LogManager.GetLogger(typeof(ErrorLogging).Name); instead of log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); Let me know if it helps. Thanks, From: Dennis Minderhoud [mailto:d...@presoft.nl] Sent: Wednesday, March 14, 2012 2:10 PM To: log4net-user@logging.apache.org; log4net-...@logging.apache.org Subject: Logger not working in an ASP.Net environment only works with full trust I've made a simple .NET 4 Web Application in VS2010, and added a reference to log4net 1.2.11.0 (latest). In this project I've made a Logger class: public static class Logger { private static readonly log4net.ILog log; static Logger() { try { log4net.Config.XmlConfigurator.Configure(); log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); } catch (Exception e) { System.Diagnostics.Debug.Write(e.ToString()); } } public static void LogInfo(string information) { log.Info(information); } public static void LogError(string erroMessage, Exception ex) { log.Error(erroMessage, ex); } public static void LogWarnings(string warningText) { log.Warn(warningText); } public static void Fatal(string fatalText) { log.Fatal(fatalText); } } When I call this Logger class (Logger.Fatal("Test");) in a Full trust environment, everything works correct. However, when I change the trust level to High (or Medium) it fails with the following exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.TypeLoadException: Inheritance security rules violated while overriding member: 'log4net.Util.ReadOnlyPropertiesDictionary.GetObjectData(System.Runtime.Serialization.SerializationInfo, System.Runtime.Serialization.StreamingContext)'. Security accessibility of the overriding method must match the security accessibility of the method being overriden. at log4net.Repository.Hierarchy.Hierarchy..ctor(ILoggerFactory loggerFactory) at log4net.Repository.Hierarchy.Hierarchy..ctor() --- End of inner exception stack trace --- at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) at System.Activator.CreateInstance(Type type, Boolean nonPublic) at log4net.Core.DefaultRepositorySelector.CreateRepository(String repositoryName, Type repositoryType) at log4net.Core.DefaultRepositorySelector.CreateRepository(Assembly repositoryAssembly, Type repositoryType, String repositoryName, Boolean readAssemblyAttributes) at log4net.Core.DefaultRepositorySelector.CreateRepository(Assembly repositoryAssembly, Type repositoryType) at log4net.Core.DefaultRepositorySelector.GetRepository(Assembly repositoryAssembly) at log4net.Core.LoggerManager.GetRepository(Assembly repositoryAssembly) at log4net.Config.XmlConfigurator.Configure() at UtilClasses.Logger..cctor() in c:\users\***\documents\visual studio 2010\Projects\TestLogging\TestLogging\Default.aspx.cs:line 35 When I include the log4net project to the solution, I get the exception when creating an instance of the default LogRepository: rep = (ILoggerRepository)Activator.CreateInstance(repositoryType); on line 412 of DefaultRepositorySelector.cs this is my web.config: <?xml version="1.0"?> <configuration> <configSections> <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net" /> </configSections> <system.web> <compilation debug="true" targetFramework="4.0" /> <trust level="High" /> </system.web> <log4net debug="true"> <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender"> <file value="logfile.txt" /> <appendToFile value="true" /> <rollingStyle value="Date" /> <datePattern value="yyyy-MM-dd" /> <layout type="log4net.Layout.PatternLayout"> <conversionPattern value="%date{dd-MM-yyyy HH:mm:ss,fff} [%-2p] - %C.%M - %m%n" /> </layout> </appender> <root> <level value="ALL" /> <appender-ref ref="RollingFileAppender" /> </root> </log4net> <system.webServer> <modules runAllManagedModulesForAllRequests="true"/> </system.webServer> </configuration> Other people suggest to add requirePermission="false" to the section, but then the debugger won't attach to the application pool. I hope someone can help me out of this problem. Regards, Dennis Minderhoud ________________________________ This message contains Devin Group confidential information and is intended only for the individual named. If you are not the named addressee you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail in error and delete this e-mail from your system. E-mail transmissions cannot be guaranteed secure, error-free and information could be intercepted, corrupted, lost, destroyed, arrive late, incomplete, or contain viruses. The sender therefore does not accept liability for errors or omissions in the contents of this message which may arise as result of transmission. If verification is required please request hard-copy version.