Data Transfers · Downloads and large files
Why does New Transfer say my link “points at a folder rather than a file”?
Short answer: The link ends at a folder, so it would download a listing page, not your file. Add the file name to the end, or copy the link from the actual download button. When it's right you'll see “Download link recognised”.
The link ends at a folder (for example it finishes with a slash), so downloading it would only save the web page that lists the folder, not the file you want. Storage Studio stops you before that happens, and Start Transfer stays greyed out.
To fix it, add the file name to the end of the link — or go back to the web page, right-click the actual download button or file, choose Copy Link, and paste that instead. When the link is right, the sheet shows "Download link recognised" with the file name.
Related: Download a file from a link