Session 'app' error while installing APK

Question

I am having difficulty importing a project written on Android Studio 1.1 into Android Studio 2.1.2. I keep getting this error whenever the gradle is building before testing

Answer 1

It's a bit late for reply but, i've figured out how to solve this problem on Android Studio 3.1.

You can have "Instant Run" checked, what you need to do it's just to build an APK

and then retry to Run your app.

Hope this help!