An undesirable thing for users of SharePoint is getting an indefinite message that has a big red "X" and the word "Error" in bold adjacent to it. The user has done something but the page does not tell what the error is and how to fix this error. It only points them to the site administrator, that is, you.
SharePoint 2010 has addressed this issue by creating a mechanism to track communications between the web front-ends and the user's requests. This is in the form of a GUID called the correlation ID. Now when a user gets his/her error page, he/she can contact the administrator and provide the correlation ID. The administrator can then track the cause of this error using the correlation ID as a reference in the ULS logs.
This recipe shows the steps to perform after the correlation ID is provided to the administrator. To induce the error with a correlation ID, we will stop the web analytics service.