Special Categories - Logging Errors & Warnings is used when an internal error occurs within the Logging Application Block while processing a Write request.
Let's say you have configured the logging Application Block with an EmailTraceListener (associated with the "General" category) and you try to log something using Logger.Write("Test", "General") but while sending the email an error occurs (SMTP is down,
port blocked, etc.) then the error information along with the original message will be logged to any Trace Listeners configured in the Logging Errors & Warnings Special Source. Usually for the Logging Errors & Warnings Special Source I
recommend using a dedicated Flat File Trace Listener since it is less likely to have an error itself.
If your code is catching an exception and you want to log that information then, yes, you will need to explicitly log the error. Or perhaps use the Exception Handling Block with a Logging Exception Handler. Another approach for dealing with these
cross cutting concerns is to use
Unity Interception with the Logging Call Handler to log the exception information (send an email).
Enterprise Library support engineer