HttpException : Unable to validate data.

[James Crowley]

Hi everyone,

My site is randomly firing off a "ExceptionHttpException : Unable to
validate data. " error on some of its forms at the moment:
-------
HttpException : Unable to validate data.
http://www.developerfusion.co.uk/Members/Private/EditProfile.aspx (Referred
by http://www.developerfusion.co.uk/Members/Private/EditProfile.aspx)
at System.Web.Configuration.MachineKeySection.GetDecodedData(Byte[] buf,
Byte[] modifier, Int32 start, Int32 length, Int32& dataLength)
at System.Web.UI.ObjectStateFormatter.Deserialize(String inputString)
-----------
I can't reproduce it myself, but several users and the automatic error
reports that have been generated indicate this. The site isn't running on a
web farm or anything, the application pool isn't being recycled, and I've
tried the standard solutions of specifying a fixed machine
validation/encryption key, and I've also tried disabling the view state mac
entirely, but the problem persists. Does anyone have any ideas what might be
triggering this?

Thanks,

- James
www.developerfusion.co.uk