Validation of viewstate MAC failed. ensure that <machineKey> configuration specifies the same validationKey and validation algorithm

问题

I am currently working on a Windows 2008 server, to create a web application. I am getting this error whenever I try and run my application.

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.

I have read online that I need to add a machine key to my web config file, however I still get the error message.

Here is my current web config file

<?xml version="1.0"?>


<configuration>
    <system.web>
        <compilation debug="true" targetFramework="4.0" />
        <machineKey validationKey='00D057688A87D8BF33008D0A3DBB5790AF8A113942A216DAC73F179B21A92A529215B38D757F17B25F08DF2F0BFD11743C57716D4954BBF4E8F7180D60ED6ECE' 
                    decryptionKey='FDB6365E13BE1A8694CF0684BE1AA3580972C143A9B53420' validation='SHA1'/>
        <authorization>
            <allow users ="*"/>
        </authorization>
    </system.web>
</configuration>

here if the full error message

[ViewStateException: Invalid viewstate. 
    Client IP: 127.0.0.1
    Port: 
    Referer: http://localhost:51339/Registration/ResetPassword.aspx
    Path: /Registration/ChangePassword.aspx
    User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.115 Safari/537.36
    ViewState: /wEPDwUKLTQ4NDk4NTQ3OGRkDZ/JArXLAjjsKSeaiULV8d+8NOM=]

[HttpException (0x80004005): 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.]
   System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +198
   System.Web.UI.ObjectStateFormatter.Deserialize(String inputString, Purpose purpose) +432
   System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter2.Deserialize(String serializedState, Purpose purpose) +8
   System.Web.UI.Util.DeserializeWithAssert(IStateFormatter2 formatter, String serializedState, Purpose purpose) +40
   System.Web.UI.HiddenFieldPageStatePersister.Load() +248
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +88
   System.Web.UI.Page.LoadAllState() +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6704
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +245
   System.Web.UI.Page.ProcessRequest() +72
   System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
   System.Web.UI.Page.ProcessRequest(HttpContext context) +58
   ASP.registration_changepassword_aspx.ProcessRequest(HttpContext context) in c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\31036172\2ef1977\App_Web_akxob5yx.3.cs:0
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +341
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69

Here is the code for the form

<form id="Form1" runat="server" action="ChangePassword.aspx" method="get"> 
   <div style="font-family:Arial">
    <table style="border: 1px solid black; width:300px">
        <tr>
            <td colspan="2">
                <b>Reset my password</b>
            </td>
        </tr>
        <tr>
            <td>
                User Name
            </td>    
            <td>

                <asp:TextBox ID="txtUserName" Width="150px" runat="server" 
                ontextchanged="txtUserName_TextChanged">
                </asp:TextBox>


            </td>    
        </tr>
        <tr>
            <td>

            </td>    
            <td>

                <asp:Button ID="btnResetPassword" runat="server" 
                Width="150px" Text="Reset Password" onclick="btnResetPassword_Click" />
            </td>    
        </tr>
        <tr>
            <td colspan="2">
                <asp:Label ID="lblMessage" runat="server"></asp:Label>
            </td>    
        </tr>
    </table>
</div>
</form>
</body>
</html>

回答1:

Follow the following steps and see if it helps

1. Go to IIS manager--> Website--> MachineKey
2. Tick Automatically generate at runtime and Generate a unique key for each application for both Validation Key and Decryption Key section.

来源：https://stackoverflow.com/questions/28946059/validation-of-viewstate-mac-failed-ensure-that-machinekey-configuration-speci