Try downloading from another software/web service. If it works, switch. If you don't want software to download
Youtube videos, use online services like KeepVid.
@ajit1>> In case you are using Firefox as your browser , you might consider the below addon
*addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/
Use Firefox Extensions to download the videos but if you want a third party software then I would recommend Portable Youtube Downloader. I have been using it for many years at places where I am not on my PC and it works just fine.
@ajit1>> In case you are using Firefox as your browser , you might consider the below addon
*addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/
Use Firefox Extensions to download the videos but if you want a third party software then I would recommend Portable Youtube Downloader. I have been using it for many years at places where I am not on my PC and it works just fine.