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

Turning off the instant run(File >>Settings >>Build,Execution,Deployment >> Instant Run), solved my issue

Answer 2

Clean and Rebuild is working fine for this problem and it is good also than other solutions.

Answer 3

You can clean your project with gradle wrapper of your project. In linux:

$./gradlew clean

In windows:

>gradlew.bat clean

Answer 4

mi users if you are facing this type of issue follow these steps:

Step 1 : generate developer options as follow Settings>>About Device>>Click 7 times on MIUI Version>> It will Generate Developer Options.

Now Enable Following...

Step 2: Setting>Additional setting> Developer options> Enable USB Debugging

Step 3: Setting>Additional setting> Developer options> Enable Install via USB Note: Its Will get Enable Only If You Insert SIM In MI Device/Phone.

Step 4: Setting>Additional setting> Developer options> Enable Verify apps over USB.

all done now run the project and test....

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non mi user:

just enable once instant run options from the settings--> Build,Execution, Deployment-->Select Instant Run and Enable Check Click On OK...

Its Will Work....

Answer 5

Trying cleaning AND rebuilding your project: In Android Studio, open up the Build tab at the top left and try both the Clean and Rebuild options.

Answer 6

In my case, going to Settings>Build, Execution, Development>Compiler>Command-line options and removing the --dry-run flag fixed it for me. Not sure why that was there in the first place, but it solved it for me.