Deleting file works but adding a file doesn't

I have been using serviio on a mac with several folders shared with some samsung TVs that play a slideshow and it all works fine.
HOWEVER serviio does NOT appear to detect that I have added a photo to the directory despite the fact that I have told serviio to scan the directory for updates every minute.
The weird thing is that if I delete a file from the directory, the TV that is playing the slideshow performs as expected & the file is no longer displayed.
But if I add a new photo to that directory... it never shows up on the TV unless I force a refresh on the serviio console.
Any ideas?

TIA

Dan

[DenyAll]

Try setting the refresh time to a larger value, say 5 or 10 minutes. It may not be getting enough time to scan your entire library and make the additions.

Thanks for responding.
I changed the refresh time to 15 minutes and it doesn't help.
I'm going to try running serviio from windows.

[zip]

check the log to see if the file has indeed been added or if there has been an error