Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cl

[dhruba.bandopadhyay]

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.

The above message is what I get in my ASP.NET 2.0 page. I have debugging turned on and for those who want to see the stack trace, see below.

In my old web site I had a frame set with a ASP page in left frame and ASP.NET 2.0 page in right frame. It was working perfectly.

Then I changed the frame set into IFRAMEs (well actually using floating/draggable/resizable IFRAMEs from http://blogus.xilinus.com/ ). Now I get the above error message when I try to load up my ASP.NET 2.0 page within a IFRAME created by http://blogus.xilinus.com/. ASP pages are fine.




Stack Trace:
[CryptographicException: Length of the data to decrypt is invalid.]
System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) +1493410
System.Security.Cryptography.CryptoStream.FlushFinalBlock() +30
System.Web.Configuration.MachineKeySection.EncryptOrDecryptData(Boolean fEncrypt, Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Boolean useValidationSymAlgo) +154
System.Web.Configuration.MachineKeySection.GetDecodedData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Int32& dataLength) +119
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +214

[ViewStateException: Invalid viewstate.
Client IP: 127.0.0.1
Port: 4945
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
ViewState: /wEPDwULLTEyMTQ2MDU5NjVkZLmM+Cz37HbivYCM/Wp5kXC0U+qx
Referer: http://localhost/main.aspx
Path: /Record/Optimiser/ASP/OptimiserOpen.aspx]

[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) +116
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +251
System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState) +4
System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState) +37
System.Web.UI.HiddenFieldPageStatePersister.Load() +220
System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +83
System.Web.UI.Page.LoadAllState() +35
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6953
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +154
System.Web.UI.Page.ProcessRequest() +86
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +18
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.record_optimiser_asp_optimiseropen_aspx.ProcessRequest(HttpContext context) +29
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +154
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +64