With Internet Explorer 8 and 9, after entering the Web Player URL, it briefly shows the login page and then displays, "The Webpage cannot be found" error or a blank screen. In some cases, this will happen after you login and the Spotfire Library is not displayed.

The "More Information" on this error says this: "This error (HTTP 404 Not Found) means that Internet Explorer was able to connect to the website, but the page you wanted was not found. It's possible that the webpage is temporarily unavailable. Alternatively, the website might have changed or removed the webpage."
 

This may be related to the PIE.htc file added for Spotfire Web Player 6.5. PIE makes IE 6 through IE 9 capable of rendering CSS3 decoration features. "Request Filtering” in IIS is blocking the site. There is a new PIE.htc file for Spotfire Web Player 6.5. This file extension may not be allowed on IIS.

1. Log into the Web Player server.
2. Open the IIS Manager.
3. Navigate to the SpotfireWeb Web Site.
4. Open the “Request Filtering” option.
5. Right-click and choose “Allow File Name Extension”.
6. Add .htc, click OK.
7. Restart IIS.

See the attached (Filename:screenshot.png) for reference.

Internet Explorer 9 does not display the Spotfire Login or Library page. Error: "The Webpage cannot be found" is reported, or a blank screen.