If you need to create a new profile that is similar to an existing profile, it may be easier to copy the existing profile and then edit the copy to make any necessary changes.  To copy a profile, highlight the profile and click the Copy button.  A window opens up to allow you to name the new profile.

You will then be prompted as to whether you would like to reset the field mapping based on a new file.  Click Yes to select a new file and No to create the new profile with the same field mapping as the original profile.  

Selecting a new file resets the field mapping and virtual fields but DOES NOT reset any other profile screens – they will be the same as the original profile.

You will need to redo your field mapping – including virtual fields - if you select a new file.  If you want to retain the virtual fields from the original profile, select No to copy it as is without changing the field mapping or virtual fields at this time.  Then edit the new profile and use the Change Data Source option - this resets the field mapping while retaining the virtual fields and all other settings.