SharePoint: The security validation for this page is invalid

Today I found myself running into the ‘famous’ “The security validation for this page is invalid” error and it cost me quite some stress figuring out what went wrong, and why I wasn’t allowed to do what I wanted, a simple change to a user profile.

The thing is that everything worked fine, until I actually added the UserProfile.Commit() to apply the changes to my profile. So after some searching the web for something that could help me further (besides the run with elevated privileges), and some helpfrom my colleague Peter we found the following article: The security validation for this page is invalid. Basically the idea is: forget the AllowUnsafeUpdates(); and add a FormDigestControl to the page you are working on, as you can see it only takes a reference:

<%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=12.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c"%>

And a control:

<SharePoint:FormDigest runat=server/>

Further info can be found on the mentioned blog.