title: Sources for Android API 24 Platform not found (Android Studio 2.1)
body: <p>In Android Studio 2.1 I was using API 24 just fine, then suddenly started seeing "Sources for Android API 24 Platform not found" warning in my AndroidManifest.xml.</p>
  
  <p><a href="https://stackoverflow.com/a/37283886/5764320">Rerunning the Android SDK Manager</a> setup in Android Studio, removing other non-supported APIs, <a href="https://code.google.com/p/android/issues/detail?id=207555" rel="nofollow noreferrer">etc</a> didn't work for me.  How do I fix this?</p>