requestvalidationmode="2.0" validaterequest="false" in web.config not working

You have to post the section of web.config,

It should be,

<system.web>
    <compilation debug="true" targetFramework="4.0" />
    <httpRuntime requestValidationMode="2.0" />
</system.web>

There was similar topic already.

ValidateRequest="false" doesn't work in Asp.Net 4

Hope this will help.

I wouldn't even try to enable this on a site-wide level in the web.config file - just do it per page, when you know specifically input data is safe:

<%@ Page ... ValidateRequest="false" %>

You can use an Umbraco control exposed specifically for this purpose from within a Template as such:

<umbraco:DisableRequestValidation runat="server" />

Related