title: Android gradle build Error "finished with non-zero exit value 42" , what does it mean and how do i fix it?
body: <p>I am trying to run an older project on what i think is the latest version of android studio. When I attempt to run or debug the app i get 2 error messages. I have Google this and found no viable solution.  </p>
  
  <p>error 1 </p>
  
  <p>Error:Error: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'E:\Android Studio\Android\sdk\build-tools\21.1.2\aapt.exe'' finished with non-zero exit value 42</p>
  
  <p>error 2 </p>
  
  <p>Error:Execution failed for task ':app:mergeDebugResources'.</p>
  
  <blockquote>
    <p>E:\tuts\Developing Android Apps {AM}\Exercise Files\Ex_Files_DevelopAndroidApp_EssT\Ex_Files_DevelopAndroidApp_EssT\Exercise Files\Solutions\04_Layouts\RegistrationSolution\app\build\intermediates\exploded-aar\com.android.support\appcompat-v7\21.0.3\res\drawable-mdpi\abc_btn_switch_to_on_mtrl_00012.9.png: Error: com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command 'E:\Android Studio\Android\sdk\build-tools\21.1.2\aapt.exe'' finished with non-zero exit value 42</p>
  </blockquote>
  
  <p>What do the errors mean and how do i fix them? 
  <img src="https://i.stack.imgur.com/44zBi.png" alt="here you can see the Android Studio "></p>
  
  <p>I tried closing and opening and android studio think it may help somehow 
  <img src="https://i.stack.imgur.com/16cRs.png" alt="Image of Event Log"></p>