To set it as the default, please disable the others that are not in use.

Thanks for the reply. However, even after disabling all the downloaders that I could see in "Add-ons" and "Extensions", Star Downloader didn't activate. Also, when I tried to manually add the video URL, all I got was a 19 second file downloaded.

Sorry, but this is a third party product and I can't help you.
Please visit the website's support page and seek further help.

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