ViewState issue - asp.net

Question

We are using our website on Windows server 2003 with IIS 6 and also have a test server 2003 with IIS 5.
When I tested the page with ViewState on test server, it worked fine. But we tested on other server which is running IIS 6.It gave error. I compared web configuratioin file, it looked the same. There was the machine key and maximum length for view state. I've been spending couple days and still don't find it. Somebody can help me.
This error doesn't happen all the time. So I think the source code is not the problem.
Here is my error
[SerializationException: Member '_name' was not found.]
System.Runtime.Serialization.SerializationInfo.GetElement(String name, Type& foundType) +7608149
System.Runtime.Serialization.SerializationInfo.GetString(String name) +24
SD.LLBLGen.Pro.ORMSupportClasses.EntityBase2..ctor(SerializationInfo info, StreamingContext context) +69
PV.Data.Standard.EntityClasses.ClinicEntity..ctor(SerializationInfo info, StreamingContext context) +26
[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeMethodHandle._SerializationInvoke(Object target, SignatureStruct& declaringTypeSig, SerializationInfo info, StreamingContext context) +0
System.Reflection.RuntimeConstructorInfo.SerializationInvoke(Object target, SerializationInfo info, StreamingContext context) +108
System.Runtime.Serialization.ObjectManager.CompleteISerializableObject(Object obj, SerializationInfo info, StreamingContext context) +273
System.Runtime.Serialization.ObjectManager.FixupSpecialObject(ObjectHolder holder) +49
System.Runtime.Serialization.ObjectManager.DoFixups() +223
System.Runtime.Serialization.Formatters.Binary.ObjectReader.Deserialize(HeaderHandler handler, __BinaryParser serParser, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +188
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream, HeaderHandler handler, Boolean fCheck, Boolean isCrossAppDomain, IMethodCallMessage methodCallMessage) +203
System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Deserialize(Stream serializationStream) +12
System.Web.UI.ObjectStateFormatter.DeserializeValue(SerializerBinaryReader reader) +968
System.Web.UI.ObjectStateFormatter.DeserializeValue(SerializerBinaryReader reader) +291
System.Web.UI.ObjectStateFormatter.DeserializeValue(SerializerBinaryReader reader) +392
System.Web.UI.ObjectStateFormatter.DeserializeValue(SerializerBinaryReader reader) +404
System.Web.UI.ObjectStateFormatter.DeserializeValue(SerializerBinaryReader reader) +392
System.Web.UI.ObjectStateFormatter.Deserialize(Stream inputStream) +135
[ArgumentException: The serialized data is invalid.]
System.Web.UI.ObjectStateFormatter.Deserialize(Stream inputStream) +199
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +297
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() +113
[ViewStateException: Invalid viewstate.
Client IP: 10.0.51.92
Port: 51267
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; BRI/1)
ViewState: /wEPDwUJODUyMDU5NzIxDxYOHgpQcmFjdGljZVBrKClYU3lzdGVtLkd1aWQsIG1zY29ybGliLCBWZXJzaW9uPTIuMC4wLjAsIEN1bHR1cmU9bmV1dHJhbCwgUHVibGljS2V5VG9rZW49Yjc3YTVjNTYxOTM0ZTA4OSRlMzE4OTAzNy0xOWY3LWRmMTEtOGQwNC0wMDFlMGI2ZTE4MWEeCENsaW5pY1BrKCsEJGQyYzg3OWI4LTE5ZjctZGYxMS04ZDA0LTAwMWUwYjZlMTgxYR4IUHJhY3RpY2UFBFBDTFAeBkNsaW5pYwUKVy4gUk9CSU5TTx4M..]
[HttpException (0x80004005): The state information is invalid for this page and might be corrupted.]
System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +106
System.Web.UI.ViewStateException.ThrowViewStateError(Exception inner, String persistedState) +14
System.Web.UI.HiddenFieldPageStatePersister.Load() +217
System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +105
System.Web.UI.Page.LoadAllState() +43
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6785
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +242
System.Web.UI.Page.ProcessRequest() +80
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.clinicinfo_aspx.ProcessRequest(HttpContext context) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\9ca5f508\2be4cd8e\App_Web_sqt6xlmv.2.cs:0
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

Answer 1

I guess it's too obvious to say that your test server might serve it's purpose better if it ran on the same version of windows and IIS that your production server uses... (so that's actually one suggestion...)
Otherwise, without digging into all of the possible issues that could be causing this, you can use IIS5 compatibility mode in IIS6.
R-click your website in IIS Manager
Service
check-mark the IIS 5 Isolation mode checkbox

Answer 2

Has the SD.LLBLGen.Pro.ORMSupportClasses.EntityBase2 class ever had a member named _name? Is there load balancing involved here?
It looks like the ViewState was created on a machine where the SD.LLBLGen.Pro.ORMSupportClasses.EntityBase2 class had a _name_ member, and then the ViewState is being interpreted on a machine where that class does not have a_name` member.