Office Web Apps is one of my favorite new parts of SharePoint 2010, but there are a number of steps you need to follow to ensure that they actually work. To start with, be sure and download the Installation guide and run any scripts mentioned in there as necessary. Also, you will want to run the script mentioned in Jie Lie’s post. You also want to verify that the Word Viewer Service application is started. However, if you are like me, you may still find that you get an error like the one below.
An unexpected error has occurred.
Yes, it’s good to know that useful error message hasn’t gone away. However, we do gain something here. You will notice that I have the Correlation Id highlighted. This corresponds to an actual error message in the ULS logs in the 14 hive. What is great, is you can use the handy ULS Viewer tool, to make troubleshooting this error even easier. Simply search for that Correlation Id and you will find out what the actual error was. In my case, the answer was really quite simple as you can see from the error message.
Microsoft.Office.Web.Common.BadCanaryConfigurationException: This feature is not activated for the site collection.
If you want to use the Word Viewer, you actually need to activate the feature on the Site Collection. To resolve this, I simply activated the Office Web Apps feature.
Strangely enough, my Excel Viewer was working the entire time without this activated. If you haven’t seen Office Web Apps, here is what the Word Viewer looks like running in Chrome using Silverlight.
I’ll also mention that in the past I have gotten a yellow screen instead of an error message. This makes it difficult to determine a Correlation Id, but you can still browse the ULS logs using the ULS viewer pretty easily.