Hi, please load your slidefile using the "i" menu and it will be taken into account. The default slidefile location upon first installation is now My documents/fitaly/slidefiles which explains why your copy in the windows folder was not picked up by Fitaly. Once you load a slidefile using the "i " menu, Fitaly remembers its location, so all you need to do is load the slidefile you have copied.
Best regards,
Emmanuel