Scan and rebuild

You ARE using Twonky server; the one built in to the MyCloud. That’s what you are controlling when you hit the DLNA database scan and rebuild buttons.

You can see what Twonky thinks is the state of its database, by using the Twonky UI on port 9000 of your mycloud’s IP address. If that shows the correct number of videos after a scan, then it may be an issue with the dlna viewer on your TV.