title: Failure to install APK [INSTALL_FAILED_DEXOPT] Android Studio
body: <p>I have tried literally everything to try and rectify this error when trying to deploy an app to an actual android device for debugging but have been unable to solve the matter. Everytime I try to launch I get a failed [INSTALL_FAILED_DEXOPT] error and when checking the logcat it is always because there is no classes.dex in my debug apk. </p>
  
  <p>If I run gradlew.bat clean assembleDebug, there is no difference in the apk size so I'm assuming there is a build error in android studio. I am using android studio beta 0.86 and have tried it on 0.89 with the same result. I have tried build tools for 19.1 to 21 with no result. I have also tried different devices and created a new project (that has never been installed on my devices) and android studio seems to think it needs to be uninstalled first when attempting to deploy. </p>
  
  <p>I have tried switching my device to ART, uninstalling and reinstalling android studio, redownloading the sdk and restarting my computer. NOTHING and I mean NOTHING has worked. I think the problem started after I downloaded the lollipop apis but am not sure. I have tried uninstalling all apps with my package signature on my device but NOTHING works! Not even Project -> Clean Project -> Rebuild</p>
  
  <p>This is extremely frustrating as I cannot debug my apps anymore :/ has anyone had any experience with this error or ways to rectify it? </p>