As the article ASP.NET Configuration File Hierarchy and Inheritance says
the Web.config file for a specific Web
site contains settings that apply to
the Web site and inherit downward
through all of the ASP.NET
applications and subdirectories of the
site.
I have these settings for a "parent" application
<customErrors mode="RemoteOnly" defaultRedirect="GenericError.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
<error statusCode="500" redirect="InternalError.htm" />
</customErrors>
but need only these for a "child" application
<customErrors mode="RemoteOnly" />
The article also says
In collections, configuration settings
are typically added to the collection
via an add child element, removed by
key name via a remove child element,
or the entire collection can be
cleared via a clear child element. An
added setting in a child configuration
file overrides a setting of the same
key name in a parent configuration
file unless duplicates are allowed.
But unfortunately this is illegal for some reason
<customErrors mode="RemoteOnly">
<clear/>
<customErrors/>
So the question is how to clear inherited customErrors elements?
Best Answer
Did you try to add in the inheritInChildApplications="false" XML element to your parent's (top level) web.config?
reference: - http://www.west-wind.com/WebLog/posts/133041.aspx