Unable to validate data - static machineKey no good!! | Tech Off | Forums

Im using ASP.NET v1.1 on IIS6. The error we're receivng is:

Unable to validate data.

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: Unable to validate data.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): Unable to validate data.]
   System.Web.Configuration.MachineKey.GetDecodedData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Int32& dataLength) +194
   System.Web.UI.LosFormatter.Deserialize(String input) +60

[HttpException (0x80004005): Authentication of viewstate failed.  1) If this is a cluster, edit <machineKey> configuration so all servers use the same validationKey and validation algorithm.  AutoGenerate cannot be used in a cluster.  2) Viewstate can only be posted back to the same page.  3) The viewstate for this page might be corrupted.]
   System.Web.UI.LosFormatter.Deserialize(String input) +118
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +101

[HttpException (0x80004005): Invalid_Viewstate
	Client IP: 10.100.110.9
	Port: 3870
	User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)
	ViewState: dDwxODIxNDA0NzY0O3Q8O2w8aTwzPjs+O2w8dDw7bDxpPDE+Oz47bDx0PDtsPGk8Mz47PjtsPHQ8O2w8aTwwPjs+O2w8dDw7bDxpPDEwPjs+O2w8dDxwPHA8bDxWaXNpYmxlOz47bDxvPGY+Oz4+Oz47Oz47Pj47Pj47Pj47Pj47Pj47PkeLBXL/zG7nKk48wv4QdVhy+H4q
	Http-Referer: http://new.tillsonburg.ca/desktopmodules/admin/logon.aspx
	Path: /DesktopDefault.aspx.]
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +442
   System.Web.UI.Page.LoadPageViewState() +18


   System.Web.UI.Page.ProcessRequestMain() +447

I've made sure that the machine.config and the website web.config file have the following static key:

I've tried restarting IIS and resaving the web.config file. The error still occurs. We're using Rainbow Portal and so there are many websites using the same machine.config / web.config settings and they are fine when logging in, except for this one website. We are not using Server.Transfer within the code. Infrequently the above error DOES NOT occur and properly displays the logged in page.

Any ideas on how to resolve it?

Thank you.

Unable to validate data - static machineKey no good!!

Unable to validate data.

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