stand alone FAM 18...have used with no problems for a number of clients all of 2019 and as recently as 12/11/19.  Now, one of my client files (last used 12/11/19) won't open with error message File is not a Data File.  After typical location in my C drive\FamWin18\Clients\{190701_

        there appears the following: {190701_R.F80.

Other client files do not have this second client file number followed by _R.F80

wassup? how do I recover without having to go to my online backup company?