ASP.NET - Validation of viewstate MAC failed.

Discussion in 'General troubleshooting' started by ericsheu, Oct 12, 2010.

  1. Hi All,

    I'm getting the following error when I move my site to Winhost
    "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."

    I'm assuming Winhost is clustered so it causing problems for my application. I have read other forums about adding the machineKey to the web.config file, but it doesn't seem to help.

    Has anyone run into this issue? If you have, how did you get around it?

    Any help would be greatly appreciated!

    Last edited by a moderator: Oct 14, 2015
  2. Ray


    No. The Winhost web servers are stand alone web servers and they are not "Clustered" and they are not in a "Web Farm".

    We host each website in its unique application pool / process. To conserve memory, we recycle the application if any of the following condition is met

    1) More than 20 minutes of idle time (no http request in 20 minutes)
    2) The application uses more than 100 MB memory
    3) The application uses more than 75% of CPU time

    I suspect your application is meeting one of these conditions and your application pool is being recycled.
    Last edited by a moderator: Oct 14, 2015

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