SharePoint 2010 – This workbook cannot be opened because it is not stored in an Excel Services Application trusted location

There are some new defaults in a SharePoint 2010 environment and I stumbled upon one today in my upgraded environment. When trying to simply click on an Excel spreadsheet in a document library, I get the following:

This workbook cannot be opened because it is not stored in an Excel Services Application trusted location. To create an Excel Services Application trusted location, contact your system administrator.

Of course, I have SharePoint 2010 Enterprise (those without it, won’t experience the behavior as you won’t have Excel Services installed). The resolution is to override the document library’s (new) default behavior of wanting to open applications in the browser and instead set it to be in the Client Application (Excel, as in the software).

You can find it in: Document Library Settings, Advanced Settings under “Opening Documents in the Browser”

Furthermore, if you want to “reverse” the default behavior, there is a Site Collection Feature that you can activate, to do just that called “Open Documents in Client Applications by Default”