title: In ASP.Net, I sometimes get the following error - Viewstate verification failed. Reason: The viewstate supplied failed integrity check
body: <p>Background:  I developed a web app in ASP.Net 3.5 in C#.  It runs great but now a few users have reported that they recieve an error sometimes.  I have tried to duplicate the error but it has been hard.  One time though when I let the app sit I came back later and tried to move it along and it errored out.  I would think that has something to do with the timeout but I am using the view state. </p>
  
  <p>Any ideas?  When I look at the eventLog I do see the following error entry.</p>
  
  <p>Thank You for your help and ideas!</p>
  
  <p>John</p>
  
  <hr>
  
  <p>My event log has the following errors:</p>
  
  <p>Event code: 4005 </p>
  
  <p>Event message: Forms authentication failed for the request. Reason: The ticket supplied has expired. </p>
  
  <p>Event time: 14/03/2008 13:19:26 </p>
  
  <p>Event time (UTC): 14/03/2008 13:19:26 </p>
  
  <p>Event ID: d9f0333c2eed46e0b0207da69d2ea70e </p>
  
  <p>Event sequence: 154 </p>
  
  <p>Event occurrence: 5 </p>
  
  <p>Event detail code: 50202 </p>
  
  <hr>
  
  <p>Event code: 3005 </p>
  
  <p>Event message: An unhandled exception has occurred. </p>
  
  <p>Event time: 3/12/2009 7:49:59 AM </p>
  
  <p>Event time (UTC): 3/12/2009 11:49:59 AM </p>
  
  <p>Event ID: 590ac0f6ad734d988e9e02f0fb7800eb </p>
  
  <p>Event sequence: 52 </p>
  
  <p>Event occurrence: 1 </p>
  
  <p>Event detail code: 0 </p>
  
  <p>Application information: </p>
  
  <pre><code>Application domain: /LM/W3SVC/32/ROOT-1-128813294498061103 
  
  Trust level: Full 
  
  Application Virtual Path: / 
  
  Application Path: C:\Home\LocalUser\ucpga\Web\ 
  
  Machine name: 169349-WEB2 
  </code></pre>
  
  <p>Process information: </p>
  
  <pre><code>Process ID: 6912 
  
  Process name: w3wp.exe 
  
  Account name: NT AUTHORITY\NETWORK SERVICE 
  </code></pre>
  
  <hr>
  
  <p>Here is the latest error:</p>
  
  <p>Event code: 4009 
  Event message: Viewstate verification failed. Reason: The viewstate supplied failed integrity check. 
  Event time: 3/15/2009 10:26:27 PM 
  Event time (UTC): 3/16/2009 2:26:27 AM 
  Event ID: 3b5be134005e49c3b40400bcaa5cb48d 
  Event sequence: 56 
  Event occurrence: 1 
  Event detail code: 50203 </p>
  
  <p>Application information: 
      Application domain: /LM/W3SVC/32/ROOT-1-128816433841748972 
      Trust level: Full 
      Application Virtual Path: / 
      Application Path: C:\Home\LocalUser\ucpga\Web\ 
      Machine name: 169349-WEB2 </p>
  
  <p>Process information: 
      Process ID: 8892 
      Process name: w3wp.exe 
      Account name: NT AUTHORITY\NETWORK SERVICE </p>
  
  <p>Request information: 
      Request URL: <a href="https://hr.ucpga.org:443/application.aspx" rel="nofollow noreferrer">https://hr.ucpga.org:443/application.aspx</a> 
      Request path: /application.aspx 
      User host address: 74.160.64.222 
      User:<br>
      Is authenticated: False 
      Authentication Type:<br>
      Thread account name: 169349-WEB2\ucpga </p>
  
  <p>ViewStateException information: 
      Exception message: Invalid viewstate. 
      Client IP: 74.160.64.222 
      Port: 1251 
      User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; GTB5; .NET CLR 1.1.4322; InfoPath.1) </p>