Some Android users have reported an error relating to the Android SDK Tools location. The problem has been confirmed in many installations prior to Unity 2017.1. If this problem occurs, the best solution is to downgrade to a previous version of the SDK Tools. This can be done by following the steps outlined here:
- Locate and delete the Android SDK Tools folder [Your Android SDK Root]/tools. This location will depend on where the Android SDK package was installed. For example, on my computer the Android SDK Tools folder is found at C:\Users\cpalmer\AppData\Local\Android\sdk.
- Download SDK Tools from http://dl-ssl.google.com/Android/repository/tools_r25.2.5-windows.zip.
- Extract the archive to the SDK root directory. ...