diff --git a/dwds/CHANGELOG.md b/dwds/CHANGELOG.md
index 24ad55485..f32447dfb 100644
--- a/dwds/CHANGELOG.md
+++ b/dwds/CHANGELOG.md
@@ -13,6 +13,7 @@
   or not.
 - Pre-warm expression compiler cache to speed up Flutter Inspector loading.
 - Remove `ChromeProxyService.setExceptionPauseMode()`.
+- Display full error on failure to start DDS.
 
 ## 16.0.1
 
diff --git a/dwds/debug_extension_mv3/pubspec.yaml b/dwds/debug_extension_mv3/pubspec.yaml
index f256afbaa..86a1212ef 100644
--- a/dwds/debug_extension_mv3/pubspec.yaml
+++ b/dwds/debug_extension_mv3/pubspec.yaml
@@ -20,12 +20,9 @@ dev_dependencies:
   built_value_generator: ^8.3.0
   build_web_compilers: ^3.0.0
   dwds: ^16.0.0
-  sse: ^4.1.0
+  sse: ^4.1.2
   web_socket_channel: ^2.2.0
 
 dependency_overrides:
   dwds:
     path: ..
-  # TODO(elliette): Remove override once package:sse is published.
-  sse:
-    path: /Users/elliottbrooks/dev/sse
diff --git a/dwds/lib/src/dwds_vm_client.dart b/dwds/lib/src/dwds_vm_client.dart
index cb7c5b780..103dd52ab 100644
--- a/dwds/lib/src/dwds_vm_client.dart
+++ b/dwds/lib/src/dwds_vm_client.dart
@@ -131,7 +131,7 @@ class DwdsVmClient {
               'error': {
                 'code': kFeatureDisabled,
                 'message': kFeatureDisabledMessage,
-                'details':
+                'data':
                     'Existing VM service clients prevent DDS from taking control.',
               },
             };
diff --git a/dwds/lib/src/services/chrome_proxy_service.dart b/dwds/lib/src/services/chrome_proxy_service.dart
index aa21b3540..e9d5595e7 100644
--- a/dwds/lib/src/services/chrome_proxy_service.dart
+++ b/dwds/lib/src/services/chrome_proxy_service.dart
@@ -336,6 +336,7 @@ class ChromeProxyService implements VmServiceInterface {
   void destroyIsolate() {
     _logger.fine('Destroying isolate');
     if (!_isIsolateRunning) return;
+
     final isolate = inspector.isolate;
     final isolateRef = inspector.isolateRef;
 
diff --git a/dwds/test/debug_service_test.dart b/dwds/test/debug_service_test.dart
index 6ae1cd0b5..c7b31bb48 100644
--- a/dwds/test/debug_service_test.dart
+++ b/dwds/test/debug_service_test.dart
@@ -73,4 +73,42 @@ void main() {
             .then((ws) => ws.close()),
         completes);
   });
+
+  test('Refuses to yield to dwds if existing clients found', () async {
+    final ddsWs = await WebSocket.connect(
+      '${context.debugConnection.uri}/ws',
+    );
+
+    // Connect to vm service.
+    final ws = await WebSocket.connect('${context.debugConnection.uri}/ws');
+
+    final completer = Completer<Map<String, dynamic>>();
+    ddsWs.listen((event) {
+      completer.complete(json.decode(event as String));
+    });
+
+    const yieldControlToDDS = <String, dynamic>{
+      'jsonrpc': '2.0',
+      'id': '0',
+      'method': '_yieldControlToDDS',
+      'params': {
+        'uri': 'http://localhost:123',
+      },
+    };
+
+    // DDS should fail to start with existing vm clients.
+    ddsWs.add(json.encode(yieldControlToDDS));
+
+    final response = await completer.future;
+    expect(response['id'], '0');
+    expect(response.containsKey('error'), isTrue);
+
+    final result = response['error'] as Map<String, dynamic>;
+    expect(result['message'], 'Feature is disabled.');
+    expect(result['data'],
+        'Existing VM service clients prevent DDS from taking control.');
+
+    await ddsWs.close();
+    await ws.close();
+  });
 }