Clicking on PDFs starts download, but download terminates with message such as this one (per Grab). Very frustrating. Work around of Ctrl-save file to a location, then go to the location to open, is poor solution.

I'm not able to post the .tif here, but the message runs: Download Error /.../{filename}.pdf could not be opened, because an unknown error occurred. Try saving to disk first and then opening the file.