title: How to decide where to store per-user state? Registry? AppData? Isolated Storage?
body: <p>When should the Windows Registry be used for per-user state, and when should we use the filesystem, particularly the user's AppData folder? (eg, C:\Users\USERNAME\AppData). Where does Isolated Storage come in? </p>
  
  <p>Is there a pretty firm rule, or is it just a fuzzy thing, like "use the registry until it becomes too much data to store in the registry".  or "use whatever you feel like using."</p>
  
  <p>Are there Windows logo requirements that affect the decision?</p>
  
  <p>If I use the AppData directory, how do I choose between Local, Roaming and LocalLow ?</p>
  
  <p>edit: I just noticed these similar questions: </p>
  
  <ul>
  <li><a href="https://stackoverflow.com/questions/268424/when-and-why-should-you-store-data-in-the-windows-registry">When and why should you store data in the Registry?</a> </li>
  <li><a href="https://stackoverflow.com/questions/6607/registry-vs-ini-file-for-storing-user-configurable-application-settings">Registry vs Ini file for storing user-configurable app settings</a>. </li>
  </ul>
  
  <p>I will summarize replies. </p>