Correlation ID Error in SharePoint 2010

This error message is not new and I think most SharePoint admin/user see this message before. SharePoint 2010 display such message with a very long Correlation ID, which is indeed not very useful for debugging or tracing purpose.

I got this message again in a new SharePoint 2010 environment so I try to check out the Windows Event Log for more details:

The error mentions a control template file (TaxonomyPicker.ascx), and it's something wrong when loading or compiling the control. Fortunately I found this useful post from google immediately:

TaxonomyPicker.ascx has a line like this:
 <%@ Control className="TaxonomyPickerControl" Language="C#" Inherits="Microsoft.SharePoint.Portal.WebControls.TaxonomyPicker&#44;Microsoft.SharePoint.Portal, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

Replace the '&#44;' with a ',' (all without the quotes).

Exactly! I really see the &#44; when I open the TaxonomyPicker.ascx. So I change it and then the SharePoint site is back.