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error occur in

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machinekey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
Updated 6-May-14 19:50pm

follow the link for more info:

Validation of viewstate

To fix this need to set the EnableViewStateMAC property to false.

else you can also try this:


Hope it helps :)
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[no name] 6-May-14 5:59am    
EnableViewStateMAC its not secure for all time
Sanket Saxena 6-May-14 6:09am    
did it resolves your issue or not?
[no name] 6-May-14 6:11am    
no.still trying.
Sanket Saxena 6-May-14 6:13am    
alright see my updated ans... a new link added.
[no name] 6-May-14 6:18am    
ya i saw ur article i couldn't understand anything
<machineKey validation="SHA1" validationKey="A1B2C3D4E5F6F6E5D4C3B2A1A1B2C3D4E5F6F6E5D4C3B2A1A1B2C3D4E5F6F6E5D4C3B2A1A1B2C3D4E5F6F6E5D4C3B2A1A1B2C3D4E5F6F6E5D4C3B2A1B2C3D4E5" decryption="Auto" decryptionKey="A1B2C3D4E5F6F6E5D4C3B2A1A1B2C3D4E5F6F6E5D4C3B2A1"/>

I was wrote this code in vs2012 ultimate.u can wrote this code in wbconfg...
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If you have more than one server that hosts your ASP.NET app, you should use the same machine key on all the servers. Otherwise, when a page served by one server posts back to another server, the second server will not be able to validate the viewstate.

Check this link for more information.[^]
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