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

For me the problem was that the app I was trying to launch was already installed under a different user account on my phone. I saw this when I went to Settings->apps looking to uninstall it. I switched to the other user, uninstalled it, came back to the original user, and was able to install and launch the app from Android Studio with no more problems.

Answer 2

Just Run --> clean and rerun , In my case it helps. Prompts automatically like following message

would you uninstall already installed activity with same name

if activity is already installed first uninstall it and make project ready after installing app.

Answer 3

I was facing the same problem in android studio 2.1.2 but worked after selecting Build -> Clean Project or alternatively Run -> Clean and Rerun

Answer 4

I tried all suggested answers. I found out this is a hardware issue on Android N phone with studio 2.3 version. App launches fine on phones below version 7.

Answer 5

I did all suggestions above, but they didn't work! I rebuilt the project, uninstalled the app from my real device, unplugged USB, then I run Android Studio and run the app on my real device and the issue was gone.

Hope this helps!

Answer 6

If you are using Android 7.0 and above it is likely that the app was installed in two places (Guest and Admin) and you only Uninstalled it for only one user and that is causing problems.

To solve that, go to: Settings -> Apps & Notifications -> See all Apps -> find the app you are trying to install.

Then click the menu on the top right corner and select Uninstall for all users

Run Your App from Android Studio it should work.