Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster
<p>I've read countless posts on this topic, and tried several solutions but I'm still seeing this error.  I'm running iis6, .NET 2.0 on a single server.  When clicking a link on my form, and new page is opened that allows the user to enter a bunch of data (it's an order form).  When clicking save, I see this error:</p>

<p>"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."</p>

<p>I've verified that the page has finished loading before clicking the save button.</p>

<p>I've tried:</p>

<ul>
<li><p>adding enableViewStateMac="false" to the Page directive</p></li>
<li><p>adding this to the web.config <code>&lt;machineKey validationKey="AutoGenerate,IsolateApps"
                               decryptionKey="AutoGenerate,IsolateApps"
                               validation="SHA1"/&gt;</code></p></li>
<li><p>adding viewStateEncryptionMode="Never"in the page tag in the web.config</p></li>
<li><p>adding enableEventValidation="false" in the page tag in the web.config (which I'm not sure I should do)</p></li>
<li><p>adding renderAllHiddenFieldsAtTopOfForm="false" in the page tag in the web.config</p></li>
</ul>

<p>And I've checked for coding errors, but everything is working fine locally.  Does anyone have another suggestions?  Thanks</p>
