Thanks, Tore. The first technique you provided is the one I've already been using successfully with most links. It's just those links to one web site, and formatted per my question, where it fails. A closer look shows that what URDownloadToFile downloads under those conditions actually is some html code for that company's log-in page, even though I've already logged into the site. Same outcome with the second method. So maybe the site is interpreting the download request as coming from a separate, unvalidated session and responding with a log-in form, rather than the requested file. Since using a browser to manually download the file does work, without logging on a second time. I suspect that the eventual solution may involve automation of the web browser control, or some 3rd-part product. I'll keep digging.