Unhandled Error

I have searched through the application and found several error/execption pages, but none that appear to construct one like the above.

Can anyone help? :)

it's not a page, it's actually a function of the logging provider. If theres an error the logging provider tries to log it. By default the logging provider uses the database (DBLoggingProvider in your web.config), so if the database is not available the error can't be logged. In this case the error is written to the output stream so is visible. The actual error text comes from the exception, in this case sqlexception, which shows the failed user. This information is not hugely useful to anyone as it's a windows authenticated user, so theres not an easy way for potential hackers to use the details. However if you want to remove these messages edit Library\Components\Shared\HtmlUtils.vb and update the WriteError function so it doesn't write out the message parameter.

Cathal