How to clear inherited customErrors elements in Web.config?

Question

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?

Answer 1

Did you try to add in the inheritInChildApplications="false" XML element to your parent's (top level) web.config?

<location inheritInChildApplications=”false”>

reference: - http://www.west-wind.com/WebLog/posts/133041.aspx

Answer 2

CustomErrors isn't a collection like other config settings - you're not <add />ing the error handlers, so you can't clear them - indeed looking at the docs, the only Child of the CustomerErrors element is <error>.

Also, having set the child application to "RemoteOnly" you aren't supplying any custom errors to show to remote users - is that really what you want? Shouldn't you at least be supplying a different DefaultRedirect? Otherwise you'll be showing users the useless yellow "There was an error, but I can't show you the details" page.