Server Error in '/Laserfiche' Application.

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.

See http://go.microsoft.com/fwlink/?LinkID=314055 for more information.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.Web.HttpException: 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.

See http://go.microsoft.com/fwlink/?LinkID=314055 for more information.

Source Error: 


[No relevant source lines]

Source File: c:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\laserfiche\cb19cd8f\cc932038\App_Web_5p4qrdpi.17.cs    Line: 0 

Stack Trace: 


[ViewStateException: Invalid viewstate. 
	Client IP: ::1
	Port: 50443
	Referer: http://localhost/laserfiche/Login.aspx?db=L161
	Path: /laserfiche/Login.aspx
	User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.103 Safari/537.36
	ViewState: 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...]

[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.

See http://go.microsoft.com/fwlink/?LinkID=314055 for more information.]
   System.Web.UI.ViewStateException.ThrowMacValidationError(Exception inner, String persistedState) +12531356
   System.Web.UI.ObjectStateFormatter.Deserialize(String inputString, Purpose purpose) +12424295
   System.Web.UI.Util.DeserializeWithAssert(IStateFormatter2 formatter, String serializedState, Purpose purpose) +67
   System.Web.UI.HiddenFieldPageStatePersister.Load() +12424507
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +12678373
   System.Web.UI.Page.LoadAllState() +51
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +12671271
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +12670781
   System.Web.UI.Page.ProcessRequest() +119
   System.Web.UI.Page.ProcessRequest(HttpContext context) +99
   ASP.login_aspx.ProcessRequest(HttpContext context) in c:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\laserfiche\cb19cd8f\cc932038\App_Web_5p4qrdpi.17.cs:0
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +913
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +165

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.34237