SharePoint (and Project Server) Shenanigans

I was recently asked to look at an Excel Services problem, where rather then a spreadsheet opening in the browser we were getting the ever helpful “An unexpected error has occurred” screen.

Checking in CA the Excel Services service application seemed to be provisioned, the settings seemed okay and the service was running, a quick check in Windows event log soon found the problem

The service application was not registered with the default web application.

As soon as we set the association, Excel Services sprang into life