ViewState integrity check and invalid authentication ticket failures
<p>Before anyone says it, Yes we have validation &amp; machine key explicitly specified in Web.config</p>

<p>Yet we are still getting this error from time to time. I've spent an awful long time trying to track down this problem and have come up completely empty.</p>

<p>We do have load balancing using TMG but we've reduced the farm down to 1 server for testing, and these errors still occur, so to my mind that rules out load balancing.</p>

<p>Because both ViewState integrity checks are occurring as well as Authentication ticket failures, this to me, points squarely at a situation where the Validation and Machine keys are being regenerated periodically, But how?! is the explicit key declaration in Web.config being ignored for some reason?</p>

<p>Once upon a time our setup worked perfectly, it was only when the servers were upgraded from Server 2008 to Server 2008R2 that this started happening, everything else in terms of the web apps is the same as the old setup.</p>

<p>What I'm thinking now is, if there's any way to get those keys at run-time, so we can see if they're changing somehow?!</p>

<p>Any other ideas welcome!</p>
