This hotfix makes a new application setting available in ASP.NET 2.0. The new application setting is 'aspnet:AllowAnonymousImpersonation'. You can enable this setting by adding the following section to the Web.config file:
To enable this setting, you must have IIS 7 or IIS 7.5 running in Integrated mode. When this setting is enabled, the application runs under the security context of the IUSR identity. Additionally, creating a Forms-based Authentication Web Application will enable the setting and set it to true.
To workaround the issues, you need to determine if the setting is mandatory for your environment, and if not, you can set it to 'false'.
Be advised that editing the Authentication provider for the web application will re-set the setting to the default value (true).
AllowAnonymousImpersonation ; IUSR ;Claims; Forms Based Authentication; Sharepoint 2010; Reports;Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'; Token NT AUTHORITY\IUSR:3e3;COMException: Error HRESULT E_FAIL