What are some of the issues that can cause random problems with pdf files downloaded from a website? Sometimes they display a solid black screen, sometimes white, sometimes get a warning window that says only 'adobe', and other times they work fine. There seems to be no pattern - just a random result each time a link is clicked. Similar results in FF or IE. Seems like this should be a simple thing but haven't been able to find a solution. Any ideas would be appreciated.