Running an ASP.NET 3.51 webforms app under IIS 7.5 in a two node Windows 2008 NLB cluster and get the following intermittent error.
TypeName: System.Web.UI.ViewStateException
TypeAssembly: System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
Message: Invalid viewstate.
Client IP: 172.17.9.54
Port: 62019
User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1560.0 Safari/537.36
ViewState: /wEPDwULLTE2Mzk2NjU1NTNkZA==
The machine keys have been synchorinized in global web.conf ...
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