Sharepoint 2010 security validation error

Question

When i try to add a link to the top nav bar, I am doing this from the cms so not from code. I get the security validation invalid error. http://img233.imageshack.us/img233/5761/errorcs.png

On the internet, i can find lots of reasons why this error can occur when using your own code. The thing is that i am not using any custom code.

The only thing i use is a custom master page. When i set the site to use the standard master page i do not get the error. So obviously the error is in the master page. So my question is:

Has anyone had this problem before?

Does anyone know the solution to my problem?

Any help is appreciated.

Note : This question is still not answered

Error:

07/29/2011 11:13:54.89 w3wp.exe (0x0EAC) 0x098C SharePoint Foundation Runtime tkau Unexpected

System.Runtime.InteropServices.COMException: The security validation for this page is invalid. Click Back in your Web browser, refresh the page, and try your operation again. at Microsoft.SharePoint.Library.SPRequestInternalClass.AddNavigationNode(String bstrUrl, String bstrName, String bstrNodeUrl, Int32 lType, Int32 lParentId, Int32 lPreviousSiblingId, Boolean bAddToQuickLaunch, String& pbstrDateModified) at Microsoft.SharePoint.Library.SPRequest.AddNavigationNode(String bstrUrl, String bstrName, String bstrNodeUrl, Int32 lType, Int32 lParentId, Int32 lPreviousSiblingId, Boolean bAddToQuickLaunch, String& pbstrDateModified)

Answer 1

Can you check to see if you've included this in your masterpage?

<asp:ContentPlaceHolder id="PlaceHolderFormDigest" runat="server">
    <SharePoint:FormDigest runat="server"/>
</asp:ContentPlaceHolder>

Also, Randy Drisgill has some start master pages available on Codeplex that you can use. It has all the required content place holders on it to ensure your site functions normally.