Creating a custom error page in Umbraco CMS

In /config/umbracoSettings.config modify <error404>1</error404> "1" with the id of the page you want to show.

<errors>   <error404>1</error404> </errors>

Other ways to do it can be found at Not found handlers

As stated by other posters, modify the errors section as indicated (including culture if needed.) In addition, add the following in the web config to enable passthrough of errors to umbraco:

In /config/umbracoSettings.config (the file itself explains its usage):

<errors>  <!-- the id of the page that should be shown if the page is not found -->  <!--        <errorPage culture="default">1</errorPage>-->  <!--        <errorPage culture="en-US">200</errorPage>-->  <error404>2664</error404></errors>

In /web.config

<system.webServer>  <!-- Some other existing stuff -->  <httpErrors existingResponse="PassThrough" /></system.webServer>

(Note: This is .NET 4)

umbraco also supports culture dependent error pages in case you're working with multilingual sites...

Config changes a tiny bit. Instead of

<errors>  <error404>1050</error404></errors>

you'd now write

<errors>  <errorPage culture="default">1</errorPage>-->  <errorPage culture="en-US">200</errorPage>--></errors>

Cheers,/Dirk