Generate Machine Key:
If you sick of getting this error:
Validation of viewstate MAC failed. If this application is hosted by a Web Farm
or cluster, ensure that <machineKey> configuration specifies the same validationKey
and validation algorithm. AutoGenerate cannot be used in a cluster.
Maybe it is time to specify a machine key... just paste this into your web.config
file inside the <system.web> tag.
.net2.0
.net1.1