title: Changing machine key for exisiting asp.net application
body: <p>I have a asp.net 4.5 application with hundreds of existing users. We need to change the machine key used in the web config file. We have arrived at the point where two applications are using the same machine key and when a user logs into one application they are able to get access to the other application that uses the same machine key, despite not having an account!</p>
  
  <p>I'm aware that changing simply changing this machine key will render existing users unable to log into the system.</p>
  
  <p>Can anyone tell me if/how I can update the machine key or the existing users in such a way that I can preserve the existing user base?</p>
  
  <p>I don't know exactly what details folks may need to help me here, so I can expand on this if necessary.</p>
  
  <p>Thanks.</p>