When you convert files with MSG Viewer for Outlook, the files are automatically renamed by adding a suffix to the original file name. For example, if you are converting an MSG file named "businessproposal.msg", the file will be renamed to "businessproposal.msg.eml". This helps you better identify your files.
However, if you prefer to omit the ".msg" portion, then enable this preference. In the above example, "businessproposal.msg" would become "businessproposal.eml".
Please note that when conversions happen, files with the same exact file name will automatically be overwritten – without any notification. For this reason, it is recommended that you leave this option disabled.