How can I download some file in URL that can't be downloaded with webrequest or webclient?

Bill,

I don't think OP has a problem with Internet Download Manager. Is so, it's unlikely that the customer support of that site will help. Probably, the hassle is some detail, such as authentication, top-level protocols on top of HTTP (could be sending data in chunks), or something like that.

Only learning these detail can help. Such problems are solved with some network spy, most likely, HTTP spy would be enough. I would advise some if I knew that download with a Web browser is possible...

—SA

Hi Sergey, There are frequent changes to the major browsers as they roll out updates so often these days; download-managers like IDM which integrate into browsers (to intercept downloads and offer to handle them) struggle to keep up with the updates and changes in api's to sites like YouTube. I know through experience how frequently IDM has been updated in the last months with getting downloads from YouTube (and their automatic pop-up download selector) particularly problematic.

The screen-shot shows the OP using IDM.

On the basis of my belief that no one could be more expert at the intricacies of downloading YouTube content than IDM, and my experience of the willingness of IDM staff (small company) to give quick detailed tech support: I believe suggesting the OP write their support department is a good idea.

I see, thank you. My point is: to reproduce all the subtlety some file/media servers provide, it's possible to learn the sequence experimentally. That's why I mentioned the HTML spy.
The idea to ask IDM personnel for help should not be neglected, of course.
I would also advise to make sure that downloading of the said resource would be legitimate...
—SA

If anything can be downloaded at all, it can be downloaded with the class HttpWebRequest.
Can it be downloaded using a Web browser without installing anything extra?
—SA