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

Just disable Instant Run.

Go To File >> Settings >> Build, Execute, Deployment >> Instant Run

Uncheck The Box that says Enable instant run to hot swap code/resource changes on deploy

Re-run the emulator.