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Viewstateexception invalid viewstate
Validation of viewstate mac failed. if this application is hosted by a web farm or cluster!
Troubleshoot invalid viewstate issues
This article introduces techniques for debugging and for resolving problems with viewstate in Microsoft ASP.NET applications.
Original product version: ASP.NET
Original KB number: 829743
Introduction
Viewstate is a feature in ASP.NET that allows pages to automatically preserve state without relying on server state (for example, session state).
However, issues related to viewstate can be difficult to debug. In most cases, when problems with viewstate occur, you receive the following error message in the web browser, with little indication of what might be causing the issue:
The viewstate is invalid for this page and might be corrupted.
This article describes some techniques that can be used for debugging and for resolving problems with viewstate.
Set the validationKey attribute if you're running in a Web farm
In a Web farm, each client request can go to a different machine on every postback.
Because of this behavior, y
