.Net ramblings
# Monday, 30 January 2006
Fix: Unable to validate data, MachineKey.GetDecodedData
i kept getting these sporadic error messages on my web applications and i could never figure out why. 
Unable to validate data at
System.Web.Configuration.MachineKey.GetDecodedData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Int32& dataLength) at
System.Web.UI.LosFormatter.Deserialize(String input)
searching the net just reveals a troop of similarly frustrated users without solutions.  but today i found the actual reason why, and the work-around.
this excellent post on experts-exchange has the answer.  apparently it happens when users leave a page open for a long time, and then cause a post back.  something to do with the machine key being automatically generated and it changes before the user causes the postback, and it can't validate it then. 
the fix is to set a static machine key. 
There is a kb article with some code to generate a key for you, + instructions.  

Sorted.


Monday, 30 January 2006 22:53:44 (GMT Standard Time, UTC+00:00)  #    Comments [13]  .Net General | Asp.NetTracked by:
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