Session 'app': Error Launching activity

Question

After the Android Studio 2.0 update while the gradle build finishes I get this :

Session \'app\': Error Launching activity .

It prevents the app from starting

Answer 1

Disable "instant run", you can go to Preference Dialog ( May be Setting dialog on Windows), then select Build, Execution, Deployment > Instant Run, and uncheck all the checkbox to disable Instant Run.

And Reboot your Device this should make the thing work....instant run has a bug in Android studio 2+ This should do the magic