Switch -ILOG[name] - log errors to file
Write error messages to the file rar.log created in WinRAR folder. You may view contents of this file using "View log…" command in Options menu. It is possible to specify another log file name instead of the default rar.log in the switch, for example, -ilogc:\log\backup.log. If the specified name does not include the path, the log file will be created in %APPDATA%\WinRAR folder.
If the option "Log errors to file" in General settings dialog is enabled, error messages will be written to rar.log even without -ilog switch.