If you upgraded Android Studio in December 2014, you may have encountered errors in your projects such as: Gradle DSL method not found: ‘runProguard()’ in the build.gradle file. This is because runProGuard has been renamed to minifyEnabled.
In this section:
buildTypes {
release {
runProGuard false
proguardFiles getDefaultProguardFile(‘proguard-android.txt’), ‘proguard-rules.txt’
}
}
Replace runProGuard with minifyEnabled, then click ‘Try Again’.
Source: Stack Overflow.