It doesn't have to be fully loaded. the loading you see is the buffering for the video player on the site. Double clicking the link in the Activity window opens a new window with a direct link to the video -- which then begins to download from the beginning regardless of how far along the youtube player has loaded.Make sure your video is fully loaded. Then download the program iSquint. Then on the youtube page, go to the tab Window then select Activity. From there find the largest file possible, usually a few MB. Double click and it will be downloaded as "get_vid." It will be in your downloads folder. Open up iSquint and drag the "get_vid" to iSquint and start the conversion.