I have 2 Web forms, let&#039;s call them Form1.aspx and Form2.aspx. Form1 needs to send a form post to Form2. When I click the Submit button, I get an "Unable to validate data" error and I see an "Invalid_Viewstate" error. It looks like Form 1 is sending the "_ViewState" hidden field to Form2 and that is causing the problem.<BR>However, on both Form1 and Form2, I have the "enableViewState" set to "False". I did this on both the Properties of the designer and via code in the CodeBehind pages as well. So I don&#039;t see why Form1 is sending its ViewState to Form2. Has anyone seen this before? Thanks.<BR><BR>Note: The Exceptions Details is "System.Web.HttpException: Unable to validate data."<BR>