Concert Log File Location
The Net3 Concert log file is located in the Local AppData Temp directory.
In Net3 Concert v3.0 and higher, the Help > About Net3 Concert window contains a link to this folder:
On most Windows systems, this would be:
C:\Users\%username%\AppData\Local\Temp\Net3 Concert\concert_log_....txt
Or
%LOCALAPPDATA%\Temp\Net3 Concert\concert_log_.....txt
You may need to enable Windows to "Show hidden files, folders, or drives" in order to access this folder.