title: ASP.NET Validation of viewstate MAC failed
body: <p>I've a listView to show list of data. It was all good and suddendly we are receiving the error message below:</p>
  
  <blockquote>
    <p>Validation of viewstate MAC failed. If
    this application is hosted by a Web
    Farm or cluster, ensure that
    configuration specifies the same
    validationKey and validation
    algorithm. AutoGenerate cannot be used
    in a cluster.Invalid viewstate. Client
    IP...User-Agent: Mozilla/4.0
    (compatible; MSIE 7.0; Windows NT 5.1;
    .NET CLR 1.1.4322; .NET CLR 2.0.50727;
    .NET CLR 3.0.4506.2152; .NET CLR
    3.5.30729; InfoPath.3) ViewState:</p>
  </blockquote>
  
  <p>Could anyone please guide me through how to fix this issue. Please note:
  1. Our IIS Server is standalone not a farmed.</p>
  
  <p>Update:
  The ListView has hyperlink to records where uses can click.
  Thanks heaps.</p>