Flutter Android build errorFlutter: “Gradle build failed to produce an .apk file. It’s likely that this file was generated under …/build, but the tool couldn’t find it.”

Why flutter can’t find the APK, and the fix

1. 01

   Product flavors, but no --flavor

   “Replace this with the name of your Android product flavor” Flutter, Set up flavors for Android

   With flavors defined, Gradle names the files app-staging-debug.apk and so on, while flutter without --flavor looks for app-debug.apk. Pass the flavor every time, also in your IDE run configuration.

   flutter run --flavor staging
   flutter build apk --flavor production --release

2. 02

   A custom APK file name

   On current stable Flutter, a block in android/app/build.gradle that sets outputFileName (for example to add the version) changes the name flutter expects. Remove it, or copy and rename the APK in a script after flutter build apk. Newer Flutter builds copy the APK under the expected name, so this cause fades after upgrading.

   // Groovy: remove blocks like this from android/app/build.gradle
   applicationVariants.all { variant ->
       variant.outputs.all { outputFileName = "myapp-${variant.versionName}.apk" }
   }

3. 03

   The build folder was moved

   Flutter’s Android template sends Gradle output to the project’s top-level build folder. If those lines were removed or changed in android/build.gradle.kts (or android/build.gradle in older Groovy projects), the APK lands somewhere the tool doesn’t look. Restore them from a fresh flutter create project.

   // android/build.gradle.kts (from the Flutter template)
   val newBuildDir: Directory =
       rootProject.layout.buildDirectory
           .dir("../../build")
           .get()
   rootProject.layout.buildDirectory.value(newBuildDir)
   
   subprojects {
       val newSubprojectBuildDir: Directory = newBuildDir.dir(project.name)
       project.layout.buildDirectory.value(newSubprojectBuildDir)
   }
   
   // android/build.gradle (older Groovy projects)
   rootProject.buildDir = "../build"
   subprojects {
       project.buildDir = "${rootProject.buildDir}/${project.name}"
   }

Checked against the vendor’s docs on November 8, 2026: Flutter: Set up flavors for Android; Flutter tool source: where flutter looks for the APK (gradle.dart); Flutter template: android/build.gradle.kts.

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Related: Android “Execution failed for task” · Flutter “:app:compileFlutterBuildDebug” failed · Gradle “Could not resolve all files” · Flutter Gradle assembleDebug failed