Why does my `NLog` logging command not log anything (despite NLog.config)?

Question

I'm using NLog library for logging purposes.

I have declared the following class:

public partial class FenetrePrincipale : Form
{
    #region NLog
    private static readonly Logger logger = LogManager.GetLogger("FenetrePrincipale");
    #endregion
...

I run over the following lines of source code:

private bool StartService()
{
    try
    {
        logger.Debug("Try to start service");

My NLog.config looks as follows:

<?xml version="1.0" encoding="utf-8"?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd">

  <targets>
    <target name="file"
            xsi:type="File"
            fileName="${basedir}/${date:format=yyyyMMdd}.log"
            layout="${longdate} | ${level:uppercase=true} | ${message}" />
  </targets>

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

</nlog>

... but no logfile gets created, although I'm sure i'm in the right directory (check the PID in Visual Studio, look for that in Windows Task Manager, and choose "Open file location" in the context menu).

Is there a way to alter logger.Debug(text); into logger.Debug(text,explanation) where the explanation is filled in by NLog and tells me why no logfile is created? (I don't believe this exists: I have decompiled NLog and I didn't find Debug(..., out ...))
Is there another way to find out what's going wrong?

For your information: it has worked before in that directory, it's certainly not a problem with file permissions or so.

Edit:
As proposed by Fildor, I have modified my nlog.config file as follows:

<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xsi:schemaLocation="http://www.nlog-project.org/schemas/NLog.xsd NLog.xsd"
      internalLogFile="c:\Temp_Folder\log.txt" internalLogLevel="Trace">

... but no result:

Command prompt>dir c:\Temp_Folder\log.txt
...
 Directory of c:\Temp_Folder

File Not Found

However, my NLog.dll seems recent enough:

... and the mentioned GitHub URL mentions quite regularly "introduced with NLog 4.3".

As far as NLog in my solution is concerned, this is what the solution looks like:

Is there a link with this eventlog?
In the Windows event log, "Windows Logs.System", there is following entry:

The application-specific permission settings do not grant Local Activation permission for the COM Server application with CLSID {2593F8B9-4EAF-457C-B68A-50F6B8EA6B54} and APPID {15C20B67-12E7-4BB6-92BB-7AFF07997402} to the user DOMAIN\DDM SID (S-1-5-21-1049629045-689772303-932725714-51094) from address LocalHost (Using LRPC) running in the application container Unavailable SID (Unavailable). This security permission can be modified using the Component Services administrative tool.

Edit about adding 'NLog.config' to the Visual Studio solution:
Although I didn't believe in the sense of adding NLog.config to the Visual Solution file, I did it anyway:

This, however, did not make any difference: the logfile still does not get created, neither did the internal logfile (C:\Temp_Folder\Log.txt).

As far as I remeber, there is a switch for "internal logging" that can be used to debug issues with NLog itself. (Or the config). If I remeber correctly that goes to a separate file, though. — Fildor
– Fildor, Commented Feb 27 at 14:30
See stackoverflow.com/a/60902387/982149 and/or github.com/NLog/NLog/wiki/Internal-logging — Fildor
– Fildor, Commented Feb 27 at 14:35
@Fildor: Thanks a lot for your quick reply, but it seems not to work, as you can see in the edit of my question. — Dominique
– Dominique, Commented Feb 27 at 14:51
How can I be sure that NLog is taking my nlog.config file into account? As mentioned, it's located in the same directory as my application. — Dominique
– Dominique, Commented Feb 27 at 15:09
@Dominique Pretty sure the EventLog-entry is not related to not being able to load/find the NLog.config-file. Again I suggest enabling the NLog InternalLogger from code to see why it cannot load the NLog.config-file. — Rolf Kristensen
– Rolf Kristensen, Commented Feb 28 at 17:54

user1326493 · Accepted Answer · 2025-02-27 15:07:12Z

3

Took your 'NLog.config', and it works pretty fine.

Ensure the 'NLog.config' is marked as 'Copy if newer' in the Visual studio file Properties. The config file has to be copied in the output directory.

The initial NLog.config will produce a file like '20250227.log'

answered Feb 27 at 15:07

user1326493

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4 Comments

Dominique Feb 27 at 15:11

NLog.config does not even appear in Visual Studio: there is only the reference to the main library, but that has worked before. I'll show what it looks like in question I'm about to edit.

Dominique Feb 27 at 15:28

In top of this, I don't have such a result anywhere: C:\>dir /S /B "20250227.*" results in File Not Found.

user1326493 Feb 27 at 16:15

Maybe try NLog code config github.com/NLog/NLog/wiki/Configure-from-code

Dominique Feb 28 at 8:29

Although it might be possible to enforce configuring NLog from within the source code, I prefer solving this issue without modifying the code too much (NLog is being used over all our projects and I prefer not to need modifying the code in case something goes wrong).

Gael Piveteau · Accepted Answer · 2025-02-27 15:06:57Z

2

On line 4 your schema location feels wrong, you might try to remove the ending NLog.xsd. also you can try to add throwExceptions="true". It helps find conf issues.

Something like that :

<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  autoReload="true"
  throwExceptions="true"
  internalLogLevel="Info" internalLogFile="yourFilePath">

answered Feb 27 at 15:06

Gael Piveteau

314 bronze badges

1 Comment

Dominique Feb 27 at 15:30

I've added the "autoreload" and the "throwExceptions" but no results yet. Thanks for the tip, though.

Dominique · Accepted Answer · 2025-02-28 14:27:37Z

1

What is BY FAR the easiest reason for a NLog.config file not to be taken into account?

Simple:

NLog is already configured elsewhere!

In my case: there are quite some Application_Name.config files, containing the <nlog tag.

... but why didn't I find the logfiles, created by those <nlog tags?

Don't laugh: this is what it looks like:

<nlog ...
  <variable name="logDirectory" value="\\fileserver\...

=> If by default, logs are written to a server, outside of your own computer, obviously you won't find anything while searching your PC 😀

answered Feb 28 at 14:27

Dominique

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