title: Stopping caching prevents a clickonce installer from installing?
body: <p>We have a WCF click-once install application being served from an IIS website over HTTPS. It is in a subdirectory of another site which does have authenticaton (Mixed mode, both windows and form) but not applied to this folder. It also has a very high duration static cache configured, which caused us issues with our WCF app so we disabled caching in that foloder and all of a sudden the setup.exe stopped working correctly (If you went straight to the .application it worked).</p>
  
  <p>We've found a work-around, setting a 5-second cache seems to fix the issue, but I was wondering if anyone could shed some light on why this would happen? The config change that fixed it was swapping the web.config in the subfolder from:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration&gt;
   &lt;system.webServer&gt;
      &lt;staticContent&gt;
        &lt;clientCache cacheControlMode="DisableCache" /&gt;
      &lt;/staticContent&gt;  
   &lt;/system.webServer&gt;
  &lt;/configuration&gt;
  </code></pre>
  
  <p>To:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;configuration&gt;
   &lt;system.webServer&gt;
      &lt;staticContent&gt;
        &lt;clientCache cacheControlMode="UseMaxAge" cacheControlMaxAge="00.00:00:05" /&gt;
      &lt;/staticContent&gt;  
   &lt;/system.webServer&gt;
  &lt;/configuration&gt; 
  </code></pre>
  
  <p>And we tried changing back and the issue reappeared, so it's not as simple as an app pool recycle fixing it. The really weird thing is it's not happening to our staging environment, where the only difference is that it's not served over HTTPS...</p>
  
  <p><strong>Edit:</strong> Just to clarify this, I know there's not really any way to fully diagnose this. I'm quite happy to accept any rational explanation that could cause the affect described cause I don't think I could produce this effect even if I tried...</p>