Invalid postback or callback argument

I keep logging several errors listed below. I have atlas running on my site with update panels on several pages. This error seems to occur if the user uses the browser "Back" button. Is there a way to handle or prevent this error?

Error on Page: /NewestMembers.aspx Error Date/Time: Aug 29, 2006 - 6:57:37 AM Error Message: Invalid postback or callback argument. Event validation is enabled using in configuration or in a page. For security purposes, this feature verifies that arguments to postback or callback events originate from the server control that originally rendered them. If the data is valid and expected, use the ClientScriptManager.RegisterForEventValidation method in order to register the postback or callback data for validation. Error Source: System.Web Session Variables: Query String Variables: Form Variables: __EVENTTARGET = ctl00$_MainContentPlaceHolder$_NewestMembersGridView __VIEWSTATE = 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 __EVENTVALIDATION = 2YRA4zH2000xi7Lksp82pi1+tHABGzOHht7Et+u77Weu3g/BHP9mPNIn43W1htX8pl8A+lgBfwaLZ1wEqFInQUSD95SpvsF87mANctA9ZJk= __VIEWSTATEENCRYPTED = ctl00$_MainContentPlaceHolder$ScriptManager1 = ctl00$_MainContentPlaceHolder$_upNew __EVENTARGUMENT = Page$2 __PREVIOUSPAGE = zubEIIwaLs1mi-rZEVX2KuSBbYvdLRKqzF9n-nadHR81 Error Stack Trace: at System.Web.UI.ClientScriptManager.Valid ateEvent(String uniqueId, String argument) at System.Web.UI.Control.Valid ateEvent(String uniqueID, String eventArgument) at System.Web.UI.WebControls.GridView.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.GridView.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postD ata) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Hi,

I don't know your scenario but you could try to give a look tothis article by Joteke and see if it could be your case.

All of my pages are using the object datasource. I'm not doing any manual databinding.

Any other ideas out there?

Thanks for your suggestion

I have the same problem.

Here is my scenario. I have an update panel along with an AutoCompleteExtender. I have a DropDownList with an autopost back to make changes to the ContextKey property of the AutoCompleteExtender on SelectedIndexChange. which is causing me to get the post back error.

Any fixes for this?

Thanks,
Kam