Correlation ID in SharePoint 2010
SharePoint 2010 maintains logs in different areas. So it is very difficult to
find what exactly the error is. But SharePoint provides a id which is known as
correlation ID which is nothing but a GUID that is assigned to each conversation
a user does or a SharePoint process does.
A site collection administrator can take the correlation id and search in the
trace log to know where exactly the error occurred.
Just to remember for each entry in the trace log it contains a Correlation ID.
Also that entry contains the correlation id and some meaningful error message.
The correlation ID is exposed when an error page is displayed, and throughout
the trace logs.