Can't get Android emulator to run app after updating android studio

Question

Here is the error, everything was working fine after I updated android studio which I regret. I tried a few things but nothing has worked. The iphone emulator is running just fine. I am not using expo by the way. Please help. I have already tried different things, here is the complete error log:

error Failed to install the app. Make sure you have the Android development environment set up: https://facebook.github.io/react-native/docs/getting-started.html#android-development-environment. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
Unable to install /Users/rey/Desktop/SantiEmpleoReactNative/PushNotificationsTemplate copy/android/app/build/outputs/apk/debug/app-debug.apk
com.android.ddmlib.InstallException: INSTALL_FAILED_VERSION_DOWNGRADE
        at com.android.ddmlib.Device.installRemotePackage(Device.java:1133)
        at com.android.ddmlib.Device.installPackage(Device.java:963)
        at com.android.ddmlib.Device.installPackage(Device.java:939)
        at com.android.ddmlib.Device.installPackage(Device.java:928)
        at com.android.builder.testing.ConnectedDevice.installPackage(ConnectedDevice.java:126)
        at com.android.build.gradle.internal.tasks.InstallVariantTask.install(InstallVariantTask.java:175)
        at com.android.build.gradle.internal.tasks.InstallVariantTask.doTaskAction(InstallVariantTask.java:106)
        at com.android.build.gradle.internal.tasks.NonIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:51)
        at com.android.build.gradle.internal.tasks.NonIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:31)
        at com.android.build.gradle.internal.tasks.Blocks.recordSpan(Blocks.java:91)
        at com.android.build.gradle.internal.tasks.NonIncrementalTask.taskAction(NonIncrementalTask.kt:34)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:103)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.doExecute(StandardTaskAction.java:48)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:41)
        at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:28)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:702)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:669)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$5.run(ExecuteActionsTaskExecuter.java:401)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:402)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:394)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:92)
        at org.gradle.internal.operations.DelegatingBuildOperationExecutor.run(DelegatingBuildOperationExecutor.java:31)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:390)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:373)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.access$200(ExecuteActionsTaskExecuter.java:79)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$TaskExecution.execute(ExecuteActionsTaskExecuter.java:210)
        at org.gradle.internal.execution.steps.ExecuteStep.lambda$execute$1(ExecuteStep.java:33)
        at java.util.Optional.orElseGet(Optional.java:267)
        at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:33)
        at org.gradle.internal.execution.steps.ExecuteStep.execute(ExecuteStep.java:26)
        at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:58)
        at org.gradle.internal.execution.steps.CleanupOutputsStep.execute(CleanupOutputsStep.java:35)
        at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:48)
        at org.gradle.internal.execution.steps.ResolveInputChangesStep.execute(ResolveInputChangesStep.java:33)
        at org.gradle.internal.execution.steps.CancelExecutionStep.execute(CancelExecutionStep.java:39)
        at org.gradle.internal.execution.steps.TimeoutStep.executeWithoutTimeout(TimeoutStep.java:73)
        at org.gradle.internal.execution.steps.TimeoutStep.execute(TimeoutStep.java:54)
        at org.gradle.internal.execution.steps.CatchExceptionStep.execute(CatchExceptionStep.java:35)
        at org.gradle.internal.execution.steps.CreateOutputsStep.execute(CreateOutputsStep.java:51)
        at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:45)
        at org.gradle.internal.execution.steps.SnapshotOutputsStep.execute(SnapshotOutputsStep.java:31)
        at org.gradle.internal.execution.steps.CacheStep.executeWithoutCache(CacheStep.java:201)
        at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:70)
        at org.gradle.internal.execution.steps.CacheStep.execute(CacheStep.java:45)
        at org.gradle.internal.execution.steps.BroadcastChangingOutputsStep.execute(BroadcastChangingOutputsStep.java:49)
        at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:43)
        at org.gradle.internal.execution.steps.StoreSnapshotsStep.execute(StoreSnapshotsStep.java:32)
        at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:38)
        at org.gradle.internal.execution.steps.RecordOutputsStep.execute(RecordOutputsStep.java:24)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.executeBecause(SkipUpToDateStep.java:96)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.lambda$execute$0(SkipUpToDateStep.java:89)
        at java.util.Optional.map(Optional.java:215)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:54)
        at org.gradle.internal.execution.steps.SkipUpToDateStep.execute(SkipUpToDateStep.java:38)
        at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:77)
        at org.gradle.internal.execution.steps.ResolveChangesStep.execute(ResolveChangesStep.java:37)
        at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:36)
        at org.gradle.internal.execution.steps.legacy.MarkSnapshottingInputsFinishedStep.execute(MarkSnapshottingInputsFinishedStep.java:26)
        at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:90)
        at org.gradle.internal.execution.steps.ResolveCachingStateStep.execute(ResolveCachingStateStep.java:48)
        at org.gradle.internal.execution.impl.DefaultWorkExecutor.execute(DefaultWorkExecutor.java:33)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:117)
        at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionStateTaskExecuter.execute(ResolveBeforeExecutionStateTaskExecuter.java:75)
        at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62)
        at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108)
        at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67)
        at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46)
        at org.gradle.api.internal.tasks.execution.CleanupStaleOutputsExecuter.execute(CleanupStaleOutputsExecuter.java:94)
        at org.gradle.api.internal.tasks.execution.FinalizePropertiesTaskExecuter.execute(FinalizePropertiesTaskExecuter.java:46)
        at org.gradle.api.internal.tasks.execution.ResolveTaskExecutionModeExecuter.execute(ResolveTaskExecutionModeExecuter.java:95)
        at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:57)
        at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:56)
        at org.gradle.api.internal.tasks.execution.CatchExceptionTaskExecuter.execute(CatchExceptionTaskExecuter.java:36)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.executeTask(EventFiringTaskExecuter.java:73)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:52)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter$1.call(EventFiringTaskExecuter.java:49)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:416)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$CallableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:406)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor$1.execute(DefaultBuildOperationExecutor.java:165)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:250)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:158)
        at org.gradle.internal.operations.DefaultBuildOperationExecutor.call(DefaultBuildOperationExecutor.java:102)
        at org.gradle.internal.operations.DelegatingBuildOperationExecutor.call(DelegatingBuildOperationExecutor.java:36)
        at org.gradle.api.internal.tasks.execution.EventFiringTaskExecuter.execute(EventFiringTaskExecuter.java:49)
        at org.gradle.execution.plan.LocalTaskNodeExecutor.execute(LocalTaskNodeExecutor.java:43)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:355)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$InvokeNodeExecutorsAction.execute(DefaultTaskExecutionGraph.java:343)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:336)
        at org.gradle.execution.taskgraph.DefaultTaskExecutionGraph$BuildOperationAwareExecutionAction.execute(DefaultTaskExecutionGraph.java:322)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:134)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker$1.execute(DefaultPlanExecutor.java:129)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.execute(DefaultPlanExecutor.java:202)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.executeNextNode(DefaultPlanExecutor.java:193)
        at org.gradle.execution.plan.DefaultPlanExecutor$ExecutorWorker.run(DefaultPlanExecutor.java:129)
        at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:63)
        at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:46)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:55)
        at java.lang.Thread.run(Thread.java:748)

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:installDebug'.
> com.android.builder.testing.api.DeviceException: com.android.ddmlib.InstallException: INSTALL_FAILED_VERSION_DOWNGRADE

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 34s

    at checkExecSyncError (child_process.js:621:11)
    at execFileSync (child_process.js:639:15)
    at runOnAllDevices (/Users/rey/Desktop/SantiEmpleoReactNative/PushNotificationsTemplate copy/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:94:39)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at async Command.handleAction (/Users/rey/Desktop/SantiEmpleoReactNative/PushNotificationsTemplate copy/node_modules/react-native/node_modules/@react-native-community/cli/build/index.js:182:9)

Answer 1

Try these steps

• Uninstall the application from emulator ( If the app already installed )
• Go to android folder using cd android and clean gradle using ./gradlew clean
• Run this command adb kill-server && adb start-server
• Finally, run your app

This error may occur with the previous build versions. Therefore you need to uninstall the previous build version. somehow it makes reference to the existing cache and build version on your phone