When you preview a report in an HTML format, SQR Production Reporting Studio uses the HTML browser installed on your machine.
SQR Production Reporting Studio may be able to use your HTML browser as an internal browser to preview HTML reports directly in the Report window. Using an internal browser eliminates the need to launch an entire browser when viewing HTML output. (Currently, internal browser support is limited to Microsoft Internet Explorer, version 5.5 SP2 or greater.)
If you do not want to use an internal browser to preview your reports, you can still preview HTML using an external browser.