Hello,

   I've been encountering the following 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."
   While my aspx. page has the following characteristics:
   - is the content of a master page.
   - has 3 textboxes whose values are validated in RequiredFieldValidator, RegularExpressionValidator and CustomValidator and 1 button (asp controls).
   - is embedded with javascript.

   Error's still on even I also fixed it by adding into <%@ page %> the following properties:
   1. The first solution
      - EnableEventValidation="false"
      - ValidateRequest="false"
      - ViewStateEncryptionMode="never"
   2. The second solution
      - EnableViewStateMac="false"
   That's all.

   Please help me overcome that bug. Thanks anyway.

   Grace.