NoteWorthy Composer Forum

I see a lot of older files in my "2.75" nwc folder.

As @Flurmy  says, the conversion utility is built into NWC now. It can be invoked by typing the following at a Windows command prompt:

nwc2 -convert {input-file} {output-file}

It will automatically convert between .nwc, .mid or .nwctxt file types, based on the supplied extensions for {input-file} and {output-file} above. Unfortunately, I don't see a way to "convert" an old-style .nwc file to the current .nwc format (as @Rick G. mentioned earlier, NWC does this automatically when you open a file and save your changes.)

However, if your goal is convert the scores to MusicXML, you could convert your .nwc scores to .nwctxt, which the online converter supports. Typing the following at a command prompt will bulk convert all of the .nwc files in the current folder to .nwctxt files in a subfolder named "Converted":

for %i in (*.nwc) do "C:\Program Files (x86)\Noteworthy Software\Noteworthy Composer 2\nwc2.exe" -convert "%i" "Converted\%itxt"

If your NWC program is installed in a different location, be sure to update that in the above command. Also, the "Converted" folder needs to be created before you run the command.