KB Article: http://support.microsoft.com/kb/2123563
You have Microsoft Office 2010 applications or Microsoft Office 2007 applications installed on a client computer. From that client computer, you try to access an Office file that is stored on a web server (for example, a SharePoint server) that is configured for Basic authentication. The connection between your computer and the web server does not use Secure Sockets Layer (SSL). When you try to open or to download the file, you experience the following symptoms:
- The Office file does not open or download.
- You do not receive a Basic authentication password prompt when you try to open or to download the file.
- You do not receive an error message when you try to open the file. The associated Office application starts. However, the selected file does not open.