I have a web forms application based on Crystal Reports .NET 2003, and one of the options I present users is the choice between HTML output (using CrystalReportViewer), or export to PDF or XLS. All the reports from this application open in a new window (see http://aspalliance.com/525), which adds an additional problem with Win XP SP2. Usually, setting the pop-up blocker to “always allow pop-ups from this site” fixes the problem, but not in this recent case.
In this recent case, the popup window opened normally, and HTML output worked fine. For PDf and XLS output, the popup would open and close in an instant, with no prompt to download the file. We eventually figured out that prompting for file downloads, and downloads themselves, can be disabled with IE6 and XP SP2. Previous versions of IE allowed you to disable downloads, but the prompt disable was new to me.
Long story short, if your users aren’t being prompted to download the output file, change the IE settings by navigationg Tools >> Internet Options >> Security >> Custom Level, and make sure “Automatic promting for file downloads” and “file download” are both enabled.