Denny Lee described how to open a trace file in PowerPivot for Excel. It is something that is very important because the SSAS engine which runs PowerPivot runs inside the Excel process and doesn’t have an external connection (thus, also SQL Profiler cannot connect directly to that engine). Of course, this will be also the preferred way to diagnose user troubles when they have a big Excel file that is too wide to be moved by email to make a first diagnostic.