F-Stop does not create these files. This is probably caused from a MAC OS. See here:
http://www.cnet.com/news/invisible-files-with-prefix-are-created-on-some-shared-volumes-and-external-disks/
From F-Stop’s perspective, these files are not needed and can be deleted. You can use F-Stop’s smart album feature to create a smart album with the following options:
Condition: File name, Starts with, "." (period without quotes)
You can then choose the files you want to delete in this smart album.
Hope that helps.
Regards,
Jason Seelye
