MrDave's (David Yack) WebLog

April 2005 - Posts

Invalid ViewState and AppPool Recycles - Ever See it?

We have been helping one of our clients with an issue where users are reporting Invalid View state on their servers. 

It appears that we can track this back to occurring when the AppPool recycles.

In testing, we were also able to force this to happen if you modify the user from Network Services to another custom user or vice versa – Any user with view state from prior to the change is out of luck and will receive invalid viewstate

You might be wondering some of the common reasons for this type of error – inconsistent validationkeys in a server farm, server transfers with a second param of true, posting back to a different page, client side truncation of the viewstate field among others.

I’m curious if anyone else has seen Invalid View State errors that might be related to App Pools on IIS6 / Windows 2003?

Share your invalid view state thoughts! I’m convinced a few of these errors is enough to convince anyone to store view state server side!

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