title: Android Studio 2.3 emulator freezes / crashes
body: <p>I updated from studio 2.2 to 2.3 and here the emulator appears showing "Android is starting" and at various numbers of for example 
  "Optimizing app 22 of 45." it freezes.</p>
  
  <p>Restarting is not possible as I can not terminate "qemu-system-i386.exe" (access denied).</p>
  
  <p>I already uninstalled the emulator version 26 (version 25 had the same problem) with SDK manager 
  (even undeleted ...\AppData\Local\Android\sdk\emulator) and reinstalled it and did a lot of other things
  but nothing helps. Any ideas how I can debug the problem (can I set a longer timeout anywhere if that would be the reason) ?</p>