I always get "app-release-unaligned.apk". I can't get "app-release.apk". But before I've updated Android SDK, I can get both "app-release.apk" and "app-release-unaligned.apk" after pressing Build->Generate Signed Apk...
System Mac OS. Android Studio 1.5.1. Android SDK Tools 25.1.1. Android SDK Platform-tools 23.1. Android SDK Build-tools 23.0.3.
I found the similar problem on Android Developer Tools Google Plus
UPD1 I've used cmd to align my apk. Because I could not publish my application to google play. zipalign -v 4 your_project_name-unaligned.apk your_project_name.apk
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