Hi,
 Lately I've been getting the following page load exception showing up in my Event Viewer when a certain user logs in:
 Any Ideas?
  
  AssemblyVersion: 6.2.5
 PortalID: 0
 PortalName: Sutco Contracting, Ltd.
 UserID: 184
 UserName: GRAL
 ActiveTabID: 136
 ActiveTabName: Employee Login
 RawURL: /EmployeeLogin.aspx
 AbsoluteURL: /Default.aspx
 AbsoluteURLReferrer: http://www.sutco.ca/EmployeeLogin.aspx
 UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.72 Safari/537.36
 DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
 ExceptionGUID: c3213eba-e574-49fc-a4ae-439ed60586e0
 InnerException: 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.
 FileName: 
 FileLineNumber: 0
 FileColumnNumber: 0
 Method: 
 StackTrace: 
 Message: DotNetNuke.Services.Exceptions.PageLoadException: 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. ---> System.Web.HttpException: 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. ---> System.Web.UI.ViewStateException: Invalid viewstate. Client IP: 24.71.156.227 Port: 50156 Referer: http://www.sutco.ca/EmployeeLogin.aspx Path: /Default.aspx User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.72 Safari/537.36 ViewState: P6y8/cXmkcGTTA8J/F....--- End of inner exception stack trace --- at System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) at System.Web.UI.ViewStateException.ThrowMacValidationError(Exception inner, String persistedState) at System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) at System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState) at System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState) at System.Web.UI.HiddenFieldPageStatePersister.Load() at System.Web.UI.Page.LoadPageStateFromPersistenceMedium() at System.Web.UI.Page.LoadAllState() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---
 Source: 
 Server Name: D137