Open a *.bak file created by NWC
To open a *.nwc.bak file, from NoteWorthy Composer, go to File: Open Backup…
You have the option of creating a backup file (.bak) of your .nwc song file when you save the .nwc file. The backup file could be used if the original .nwc file became corrupted or lost. To have backup files created, in Tools: Options, File, check Backup files during save. The location where backup files will be saved is set with Tools: Options, Folders, Backup Files.
Multiple backup files can be created as you work, in case you need to go back to an earlier saved version. To the right of Backup files during save, select a number for Queue size for extra backups The back up files will be named filename.nwc.bak, filename.q1.nwc.bak, filename.q2.nwc.bak, etc.