Last night we completed a SharePoint 2010 at work and after all the testing, we deemed the upgrade a success, however coming into the office this morning, we received reports from some users that they were unable to open some of their Excel spreadsheets stored in various Document Libraries.
After some diagnosis, it turned out that the problem only effected Office 2007 and Office 2010 XML format documents and that original format Excel documents from Office 2003 and documents saved in the 2003 format were unaffected.
After initially suspecting the problem to be linked to the new Excel Services Application in SharePoint 2010, I worked to resolve the configuration of the Excel Services Application which we had left previous un-configured due to it not being required currently, however the problem persisted.
Whilst searching TechNet for the error code we were receiving I encountered a page entitled Ã¢â‚¬Å“Configure the Default Behaviour for Browser-Enabled DocumentsÃ¢â‚¬Â (http://technet.microsoft.com/en-us/library/ee837425.aspx) which details how to manage the behaviour of SharePoint for launching web compatible documents.
SharePoint 2010 features various web-enabled services and can be configured to use Office Web Apps, which is a hosted version of the applications available via Office Live WebApps. The default behaviour for SharePoint 2010 is to attempt to launch web compatible formats using the web based application, however as this is not configured in our environment the error appeared.
The resolution to the problem was simply enabling the Site Collection Feature Open Documents in Client Applications by Default. Once enabled on the Site Collection to apply the setting to all child sites, SharePoint began prompting the users to open the file with their client side installations of Excel as per the SharePoint 2007 behaviour.