The Management Console reports an error "Error importing dfs mappings. Please check the logs for details" .
The Webserver.log will log an error.
WARNING: #{980} [ConfigUtils.configureDfsMappings] Error importing DFS mappings: 212.
Error 212 translates to "No data found when expected".
The issue occurs due to a blank space present at the beginning of the CSV file.
Open the CSV file using notepad and clear the blank line from the beginning of the file.
Make sure the data in the notepad now begins from the very first row in the notepad.