Validation of viewstate MAC failed

Posted by Elliott Nash | Filed under , , , , ,

I was simply attempting to post a form from one page to another when i encountered the following error:

HttpException (0x80004005): 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.

It seems when developing with .NET 2.0 or later there is a bug in the framework which can become apparent if the following conditions are true: More...