If you use Log4Net as log engine for your applications (in my opinion is the best choice), this simple row in application configuration file can save you by a waste of time and probably by a headache too.
When Log4Net doesn’t log anything due to a configuration error it never throw an exception, and this is the expected (and correct) behavior of a log system which should never block an application due to its internal error. Unfortunately when something went wrong it is quite difficult discover the reason if you don’t have a break in your code.
With that configuration instruction Log4Net “logs” its initialization process in output windows and in Trace system.
If you add a trace listener you can also save this output in a file.
Here’s an example:
This is very useful in production environment where Visual Studio is not installed and then an output window is not available.