ASP.NET ERROR: 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" The solution is in adding to your custom _WEB.CONFIG_ file following strings under section: You can also generate your own machineKey on this site: http://aspnetresources.com/tools/keycreator.aspx [1] Links: ------ [1] http://aspnetresources.com/tools/keycreator.aspx
