I have an odd issue where as some Excel files once clicked give me the option to open or edit and then some others when clicked launch directly into Excel Services within my browser. There appears to be no continuity with it. When Excel loads within the browser I receive the workbook cannot be opened message? All trusts are set to the web app home and child trust are ticked. I do not actually require excel web services at the moment. Am I best deleting the service application. Will this affect anything else?