You are saving a file that was created with an older version of the application. Files are not backwards compatible. That is, files saved with the current version of the application cannot be read by older versions of the application. However, files saved with older versions can always be opened with newer versions of the application.

Option	Description
Make copy of original file before saving	When selected, a copy of the original file will be created. The name of the copied file is listed. The copy will not contain any changes you have made since the file was opened.
Don't make a copy of the original file	When selected, the file is in the current format. A copy of the original file is not made. Your file can no longer be opened with older versions of the application.
Don't show me this again	You will no longer be shown this warning when this open is checked. Use the drop down list to select the action to be taken when saving older version files.