Okay, thank you

Thank you for your help, it works great now.

The browser I use is Safari, I'm unsure if I have any extensions but I believe I have the latest version, the photo doesn't show the error well but the tab shows a blue line to show when a video is downloading and freezes at that point all the time at every video on Youtube.com I try to download. Sorry this took a while, I didn't realised that my post had a reply. Hopefully this helps.