Model notes (file.txt) deleted when files are converted up to version 15.00 format from a prior version. Furthermore, notes are not saved when closing and reoping files.
An unintended side-effect of an enhancement to the model notes file to update the file name and job name.
Problem fixed in version 15.02.00.00. Use a separate notes file in version 15.00.00.00 - 15.01.00.00.