proguardRelease FAILED when compiling apk with assembleRelease in Android Studio

Add this to ProGuard setting file(like proguard-rules.pro)

-dontwarn okio.**

I had to disable proguard with

minifyEnabled false

Not the best solution, but it works.


Add this to ProGuard setting file(like proguard-rules.pro)

-ignorewarnings 

I had the same problem with Gradle 1.1.0. It remembered some old class references which I have moved, and I couldn't build apk.

Try Build > Clean.

It helped me, and now I can build apk again.