diff --git a/examples/hello_world/distribute_options.yaml b/examples/hello_world/distribute_options.yaml
index 02a80ac4..e04ccea5 100644
--- a/examples/hello_world/distribute_options.yaml
+++ b/examples/hello_world/distribute_options.yaml
@@ -1,6 +1,6 @@
 output: dist/
 variables:
-  FLUTTER_ROOT: ~/fvm/versions/3.10.0
+  FLUTTER_ROOT: ~/fvm/versions/3.10.3
   # PGYER_API_KEY: your api key
 releases:
   - name: dev-profile
@@ -79,7 +79,7 @@ releases:
     jobs:
       - name: android-aab
         variables:
-          FLUTTER_ROOT: ~/fvm/versions/3.10.2
+          FLUTTER_ROOT: ~/fvm/versions/3.10.3
         package:
           platform: android
           target: aab
@@ -113,6 +113,8 @@ releases:
         package:
           platform: macos
           target: dmg
+          build_args:
+            dart-define-from-file: env.json
       - name: macos-pkg
         package:
           platform: macos
diff --git a/examples/hello_world/env.json b/examples/hello_world/env.json
new file mode 100644
index 00000000..85ade72d
--- /dev/null
+++ b/examples/hello_world/env.json
@@ -0,0 +1,3 @@
+{
+  "APP_ENV": "dev"
+}
diff --git a/examples/hello_world/lib/main.dart b/examples/hello_world/lib/main.dart
index be84e310..58ed234c 100644
--- a/examples/hello_world/lib/main.dart
+++ b/examples/hello_world/lib/main.dart
@@ -50,6 +50,10 @@ class MyHomePage extends StatefulWidget {
 class _MyHomePageState extends State<MyHomePage> {
   int _counter = 0;
 
+  String get _appEnv {
+    return const String.fromEnvironment('APP_ENV');
+  }
+
   String get _buildName {
     return const String.fromEnvironment('FLUTTER_BUILD_NAME');
   }
@@ -110,6 +114,10 @@ class _MyHomePageState extends State<MyHomePage> {
               '$_counter',
               style: Theme.of(context).textTheme.headlineMedium,
             ),
+            Text(
+              'APP_ENV: $_appEnv',
+              style: Theme.of(context).textTheme.bodyMedium,
+            ),
             Text(
               'FLUTTER_BUILD_NAME: $_buildName',
               style: Theme.of(context).textTheme.bodyMedium,
diff --git a/examples/hello_world/pubspec.lock b/examples/hello_world/pubspec.lock
index e69e7740..01d211c7 100644
--- a/examples/hello_world/pubspec.lock
+++ b/examples/hello_world/pubspec.lock
@@ -45,10 +45,10 @@ packages:
     dependency: "direct main"
     description:
       name: cupertino_icons
-      sha256: e35129dc44c9118cee2a5603506d823bab99c68393879edb440e0090d07586be
+      sha256: d57953e10f9f8327ce64a508a355f0b1ec902193f66288e8cb5070e7c47eeb2d
       url: "https://pub.dev"
     source: hosted
-    version: "1.0.5"
+    version: "1.0.6"
   fake_async:
     dependency: transitive
     description:
@@ -66,10 +66,10 @@ packages:
     dependency: "direct dev"
     description:
       name: flutter_lints
-      sha256: aeb0b80a8b3709709c9cc496cdc027c5b3216796bc0af0ce1007eaf24464fd4c
+      sha256: a25a15ebbdfc33ab1cd26c63a6ee519df92338a9c10f122adda92938253bef04
       url: "https://pub.dev"
     source: hosted
-    version: "2.0.1"
+    version: "2.0.3"
   flutter_test:
     dependency: "direct dev"
     description: flutter
diff --git a/packages/flutter_app_builder/lib/src/builders/app_builder.dart b/packages/flutter_app_builder/lib/src/builders/app_builder.dart
index f1555513..124c5a5f 100644
--- a/packages/flutter_app_builder/lib/src/builders/app_builder.dart
+++ b/packages/flutter_app_builder/lib/src/builders/app_builder.dart
@@ -65,7 +65,7 @@ abstract class AppBuilder {
     );
 
     if (processResult.exitCode != 0) {
-      throw BuildError();
+      throw BuildError('${processResult.stderr}');
     }
 
     return resultResolver.resolve(config)..duration = time.elapsed;
diff --git a/packages/flutter_app_builder/lib/src/commands/flutter.dart b/packages/flutter_app_builder/lib/src/commands/flutter.dart
index 6b1999b0..125d1b63 100644
--- a/packages/flutter_app_builder/lib/src/commands/flutter.dart
+++ b/packages/flutter_app_builder/lib/src/commands/flutter.dart
@@ -56,6 +56,12 @@ class _Flutter extends Command {
     String flutterRoot = environment?['FLUTTER_ROOT'] ?? '';
     if (flutterRoot.isNotEmpty) {
       flutterRoot = pathExpansion(flutterRoot, environment ?? {});
+      if (!Directory(flutterRoot).existsSync()) {
+        throw CommandError(
+          this,
+          'FLUTTER_ROOT environment variable is set to a path that does not exist: $flutterRoot',
+        );
+      }
       return p.join(flutterRoot, 'bin', 'flutter');
     }
     return 'flutter';
@@ -63,7 +69,7 @@ class _Flutter extends Command {
 
   Map<String, String>? environment;
 
-  withEnv(Map<String, String>? environment) {
+  _Flutter withEnv(Map<String, String>? environment) {
     this.environment = environment;
     return this;
   }
diff --git a/packages/shell_executor/lib/shell_executor.dart b/packages/shell_executor/lib/shell_executor.dart
index 23dbbbee..90d7254d 100644
--- a/packages/shell_executor/lib/shell_executor.dart
+++ b/packages/shell_executor/lib/shell_executor.dart
@@ -1,5 +1,6 @@
 library shell_executor;
 
 export 'src/command.dart';
+export 'src/command_error.dart';
 export 'src/shell_executor.dart';
 export 'src/utils/path_expansion.dart';
diff --git a/packages/shell_executor/lib/src/command.dart b/packages/shell_executor/lib/src/command.dart
index fb48ea32..229c2c08 100644
--- a/packages/shell_executor/lib/src/command.dart
+++ b/packages/shell_executor/lib/src/command.dart
@@ -30,26 +30,4 @@ abstract class Command {
       runInShell: runInShell,
     );
   }
-
-  Future<ProcessResult> run(
-    List<String> arguments, {
-    Map<String, String>? environment,
-  }) {
-    return exec(
-      arguments,
-      environment: environment,
-    );
-  }
-
-  ProcessResult runSync(
-    List<String> arguments, {
-    Map<String, String>? environment,
-    bool runInShell = false,
-  }) {
-    return execSync(
-      arguments,
-      environment: environment,
-      runInShell: runInShell,
-    );
-  }
 }
diff --git a/packages/shell_executor/lib/src/command_error.dart b/packages/shell_executor/lib/src/command_error.dart
new file mode 100644
index 00000000..a27cd290
--- /dev/null
+++ b/packages/shell_executor/lib/src/command_error.dart
@@ -0,0 +1,13 @@
+import 'package:shell_executor/src/command.dart';
+
+class CommandError extends Error {
+  CommandError(this.command, [this.message]);
+
+  final Command command;
+  final String? message;
+
+  @override
+  String toString() {
+    return (message != null) ? 'CommandError: $message' : 'CommandError';
+  }
+}