Hi all - I am am at a complete standstill re. this so went back to Unity SimpleMobilePlaceHolder asset to test build process as described un Unity Tutorial here. But still having probs. Android SDK tools Version is one here (as part of studio). I re-installed everything 12 hours ago so it is up-to-date. Unity was updated 12 hours ago to version 5.6.3p2 I have also tried replacing tools folder directory with older version of tools (see here for link to older version of tools for version) as many have tried before. Obviously I have double checked the paths are correct for JDK and SDK (C:\Users\Tim\AppData\Local\Android\sdk and C:\Program Files\Java\jdk-9). I am running everything else on normal hardware- nothing special on Windows 10. Target platform is Android Marshmallow Galaxy S8. Any help will be much appreciated! tim.