When you’re using ASP.NET AJAX and the user open your site using Firefox, the user may see an error message that says “The state information is invalid for this page and might be corrupted.” This seems to be caused by Firefox’s methods for saving session information in its cache. There is many way to solve this problem it’s depending on how extensive you want to disable the cache. In my case, I just wanted to do it on one page, so at the top of Page_Load I added:

Response.Cache.SetNoStore();

You could also set this in the page declaration with:

<%@ Page Language=C# MasterPageFile=~/MasterPage.master AutoEventWireup=true CodeFile=account.aspx.cs Inherits=Main Title=My Account EnableViewStateMac =false EnableSessionState=True EnableEventValidation =false ValidateRequest =false ViewStateEncryptionMode =Never %>

You could also add something like the below to Web.config:

<pages validateRequest=”false” enableEventValidation=”false” viewStateEncryptionMode =”Never”>