NLog 4.1.2 crashes in constructor

Question

I have a program that worked on this Monday (2018-10-01) but started to crash on Wednesday (it wasn't used on Tuesday).

The program is at a customer and in release form, so I can't debug it! The customer says that "Nothing has changed" and all the files in my program is as before.

It's a C# Winforms program and I have, via Event Viewer, found out that the crash happens when NLog is starting (in ctor).

I have tried to use internal logging but no log file is created.

Any ideas on what the problem is and/or how I should fix it?

The message in Event Viewer Application:

DCMark Winform.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.Xml.XmlException at System.Xml.XmlTextReaderImpl.Throw(System.Exception) at System.Xml.XmlTextReaderImpl.Throw(System.String, System.String[])
at System.Xml.XmlTextReaderImpl.ParseText(Int32 ByRef, Int32 ByRef, Int32 ByRef) at System.Xml.XmlTextReaderImpl.ParseText() at System.Xml.XmlTextReaderImpl.ParseElementContent() at System.Xml.XmlTextReaderImpl.Read() at System.Xml.XmlTextReader.Read() at System.Xml.XmlTextReaderImpl.Skip() at System.Xml.XmlTextReader.Skip() at System.Configuration.XmlUtil.StrictSkipToNextElement(System.Configuration.ExceptionAction) at System.Configuration.BaseConfigurationRecord.ScanSectionsRecursive(System.Configuration.XmlUtil, System.String, Boolean, System.String, System.Configuration.OverrideModeSetting, Boolean) at System.Configuration.BaseConfigurationRecord.ScanSectionsRecursive(System.Configuration.XmlUtil, System.String, Boolean, System.String, System.Configuration.OverrideModeSetting, Boolean) at System.Configuration.BaseConfigurationRecord.ScanSections(System.Configuration.XmlUtil) at System.Configuration.BaseConfigurationRecord.InitConfigFromFile()

Exception Info: System.Configuration.ConfigurationErrorsException
at System.Configuration.ConfigurationSchemaErrors.ThrowIfErrors(Boolean) at System.Configuration.BaseConfigurationRecord.ThrowIfParseErrors(System.Configuration.ConfigurationSchemaErrors) at System.Configuration.BaseConfigurationRecord.ThrowIfInitErrors()
at System.Configuration.ClientConfigurationSystem.OnConfigRemoved(System.Object, System.Configuration.Internal.InternalConfigEventArgs)

Exception Info: System.Configuration.ConfigurationErrorsException
at System.Configuration.ConfigurationManager.PrepareConfigSystem()
at System.Configuration.ConfigurationManager.GetSection(System.String) at System.Configuration.ConfigurationManager.get_AppSettings() at NLog.Common.InternalLogger.GetSettingString(System.String, System.String) at NLog.Common.InternalLogger.GetSetting[[System.Boolean, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]](System.String, System.String, Boolean) at NLog.Common.InternalLogger..cctor()

Exception Info: System.TypeInitializationException at DC.DCMark.Form1..ctor() at DC.DCMark.Program.Main()

The NLog.config file

<?xml version="1.0" encoding="utf-8" ?>
<nlog throwExceptions="true"
internalLogFile="C:/Temp/log.txt" internalLogLevel="Trace">
  <targets>
    <target xsi:type="File" name="f" fileName="${specialfolder:folder=CommonApplicationData}/Foo/Bar/Logs/Bar_${shortdate}.log"
            layout="${longdate} | ${uppercase:${level}} | ${callsite} | ${message} | ${exception:format=ToString}" />
  </targets>

  <rules>
    <logger name="*" minlevel="Trace" writeTo="f" />
  </rules>
</nlog>

EDIT: Added the App.config file

<?xml version="1.0" encoding="utf-8"?>
<configuration>
    <configSections>
        <sectionGroup name="userSettings" type="System.Configuration.UserSettingsGroup, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
            <section name="DC.DCMark.Properties.Settings" type="System.Configuration.ClientSettingsSection, System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" allowExeDefinition="MachineToLocalUser" requirePermission="false"/>
        </sectionGroup>
    </configSections>
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/>
    </startup>
    <userSettings>
        <DC.DCMark.Properties.Settings>
            <setting name="Location" serializeAs="String">
                <value>400, 100</value>
            </setting>
            <setting name="Size" serializeAs="String">
                <value>840, 900</value>
            </setting>
            <setting name="Maximised" serializeAs="String">
                <value>False</value>
            </setting>
            <setting name="Minimised" serializeAs="String">
                <value>False</value>
            </setting>
        </DC.DCMark.Properties.Settings>
    </userSettings>
</configuration>

Please be aware that throwExceptions="true" should never be used in a production environment. It is only intended for unit-testing or similar. It has many unwanted side-effects. — Rolf Kristensen
Good to know!, I only added it while I was testing to see if internal logging would be triggered, but no... — Andis59
Ex. It will cause NLog to crash your application when app.config is unreadable. — Rolf Kristensen

Andis59 Andis59 · Accepted Answer · 2018-10-06T08:49:39

I have found the error!

I found this https://stackoverflow.com/a/16332304/1009355 Which says that there is a copy of app.config created in %localappdata%\companyname\programname...

I removed all directories that had the program name in its name.

Everything works again!!

Thanks for all the help, I wouldn't have found the solution without it!

NLog 4.1.2 crashes in constructor

2 Answers