I have found that the length of the report output will either cause it to be saved as html or zip. Even though I select html to be the output format, IF the report has a large data return from sql, the report gets saved as a zip. BUT if the report has a small amount of data, then it will be saved as html file. WEIRD!!! Almost as if a config setting somewhere that says if the report turns out to be over a certain file size, save as a zip instead of the selected html format in report server. Has anyone encountered this before??