diff --git a/lib/features/base/mixin/batch_set_email_processing_mixin.dart b/lib/features/base/mixin/batch_set_email_processing_mixin.dart
index bdde3a9a5..9c3dcc239 100644
--- a/lib/features/base/mixin/batch_set_email_processing_mixin.dart
+++ b/lib/features/base/mixin/batch_set_email_processing_mixin.dart
@@ -68,10 +68,16 @@ mixin BatchSetEmailProcessingMixin on HandleSetErrorMixin, MailAPIMixin {
       final response =
           await (requestBuilder..usings(capabilities)).build().execute();
 
-      final setEmailResponse = response.parse<SetEmailResponse>(
-        setEmailInvocation.methodCallId,
-        SetEmailResponse.deserialize,
-      );
+      SetEmailResponse? setEmailResponse;
+      try {
+        setEmailResponse = response.parse<SetEmailResponse>(
+          setEmailInvocation.methodCallId,
+          SetEmailResponse.deserialize,
+        );
+      } catch (e) {
+        log('EmailAPI::$debugLabel: Failed to parse response: $e');
+        setEmailResponse = null;
+      }
 
       if (setEmailResponse == null) {
         log('EmailAPI::$debugLabel: Batch from ${start + 1} to $end returned null response');
diff --git a/test/features/base/mixin/batch_set_email_processing_mixin_test.dart b/test/features/base/mixin/batch_set_email_processing_mixin_test.dart
new file mode 100644
index 000000000..b1d9d897a
--- /dev/null
+++ b/test/features/base/mixin/batch_set_email_processing_mixin_test.dart
@@ -0,0 +1,555 @@
+import 'dart:async';
+import 'package:dio/dio.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:jmap_dart_client/http/http_client.dart';
+import 'package:jmap_dart_client/jmap/account_id.dart';
+import 'package:jmap_dart_client/jmap/core/id.dart';
+import 'package:jmap_dart_client/jmap/core/patch_object.dart';
+import 'package:tmail_ui_user/features/base/mixin/batch_set_email_processing_mixin.dart';
+import 'package:tmail_ui_user/features/base/mixin/handle_error_mixin.dart';
+import 'package:tmail_ui_user/features/base/mixin/mail_api_mixin.dart';
+import 'package:jmap_dart_client/jmap/mail/email/email.dart';
+import 'package:jmap_dart_client/jmap/core/user_name.dart';
+import 'package:model/account/authentication_type.dart';
+import 'package:model/account/personal_account.dart';
+import 'package:jmap_dart_client/jmap/core/account/account.dart';
+import 'package:jmap_dart_client/jmap/core/capability/capability_identifier.dart';
+import 'package:jmap_dart_client/jmap/core/capability/core_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/default_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/mail_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/mdn_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/submission_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/vacation_capability.dart';
+import 'package:jmap_dart_client/jmap/core/capability/websocket_capability.dart';
+import 'package:jmap_dart_client/jmap/core/session/session.dart';
+import 'package:jmap_dart_client/jmap/core/sort/collation_identifier.dart';
+import 'package:jmap_dart_client/jmap/core/state.dart';
+import 'package:jmap_dart_client/jmap/core/unsigned_int.dart';
+
+// --- Fixtures Cloned from Integration Tests ---
+
+class AccountFixtures {
+  static final aliceAccountId = AccountId(Id('29883977c13473ae7cb7678ef767cbfbaffc8a44a6e463d971d23a65c1dc4af6'));
+  static final aliceAccount = PersonalAccount(
+    'dab',
+    AuthenticationType.oidc,
+    isSelected: true,
+    accountId: aliceAccountId,
+    apiUrl: 'https://domain.com/jmap',
+    userName: UserName('Alice')
+  );
+}
+
+class SessionFixtures {
+  static final aliceSession = Session(
+    {
+      CapabilityIdentifier.jmapSubmission: SubmissionCapability(
+        maxDelayedSend: UnsignedInt(0),
+        submissionExtensions: {}
+      ),
+      CapabilityIdentifier.jmapCore: CoreCapability(
+        maxSizeUpload: UnsignedInt(20971520),
+        maxConcurrentUpload: UnsignedInt(4),
+        maxSizeRequest: UnsignedInt(10000000),
+        maxConcurrentRequests: UnsignedInt(4),
+        maxCallsInRequest: UnsignedInt(16),
+        maxObjectsInGet: UnsignedInt(500),
+        maxObjectsInSet: UnsignedInt(500),
+        collationAlgorithms: {CollationIdentifier("i;unicode-casemap")}
+      ),
+      CapabilityIdentifier.jmapMail: MailCapability(
+        maxMailboxesPerEmail: UnsignedInt(10000000),
+        maxSizeAttachmentsPerEmail: UnsignedInt(20000000),
+        emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
+        mayCreateTopLevelMailbox: true
+      ),
+      CapabilityIdentifier.jmapWebSocket: WebSocketCapability(
+        supportsPush: true,
+        url: Uri.parse('ws://domain.com/jmap/ws')
+      ),
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
+      CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
+      CapabilityIdentifier.jmapMdn: MdnCapability(),
+    },
+    {
+      AccountFixtures.aliceAccountId: Account(
+        AccountName('alice@domain.tld'),
+        true,
+        false,
+        {
+          CapabilityIdentifier.jmapSubmission: SubmissionCapability(
+            maxDelayedSend: UnsignedInt(0),
+            submissionExtensions: {}
+          ),
+          CapabilityIdentifier.jmapWebSocket: WebSocketCapability(
+            supportsPush: true,
+            url: Uri.parse('ws://domain.com/jmap/ws')
+          ),
+          CapabilityIdentifier.jmapCore: CoreCapability(
+            maxSizeUpload: UnsignedInt(20971520),
+            maxConcurrentUpload: UnsignedInt(4),
+            maxSizeRequest: UnsignedInt(10000000),
+            maxConcurrentRequests: UnsignedInt(4),
+            maxCallsInRequest: UnsignedInt(16),
+            maxObjectsInGet: UnsignedInt(500),
+            maxObjectsInSet: UnsignedInt(500),
+            collationAlgorithms: {CollationIdentifier("i;unicode-casemap")}
+          ),
+          CapabilityIdentifier.jmapMail: MailCapability(
+            maxMailboxesPerEmail: UnsignedInt(10000000),
+            maxSizeAttachmentsPerEmail: UnsignedInt(20000000),
+            emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
+            mayCreateTopLevelMailbox: true
+          ),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
+          CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
+          CapabilityIdentifier.jmapMdn: MdnCapability()
+        }
+      )
+    },
+    {
+      CapabilityIdentifier.jmapSubmission: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapWebSocket: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapCore: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapMail: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): AccountFixtures.aliceAccountId,
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapVacationResponse: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapMdn: AccountFixtures.aliceAccountId,
+    },
+    UserName('alice@domain.tld'),
+    Uri.parse('http://domain.com/jmap'),
+    Uri.parse('http://domain.com/download/{accountId}/{blobId}/?type={type}&name={name}'),
+    Uri.parse('http://domain.com/upload/{accountId}'),
+    Uri.parse('http://domain.com/eventSource?types={types}&closeAfter={closeafter}&ping={ping}'),
+    State('2c9f1b12-b35a-43e6-9af2-0106fb53a943')
+  );
+
+  static getAliceSessionWithMaxObjectsInSet(int maxObjectsInSet) => Session(
+    {
+      CapabilityIdentifier.jmapSubmission: SubmissionCapability(
+        maxDelayedSend: UnsignedInt(0),
+        submissionExtensions: {}
+      ),
+      CapabilityIdentifier.jmapCore: CoreCapability(
+        maxSizeUpload: UnsignedInt(20971520),
+        maxConcurrentUpload: UnsignedInt(4),
+        maxSizeRequest: UnsignedInt(10000000),
+        maxConcurrentRequests: UnsignedInt(4),
+        maxCallsInRequest: UnsignedInt(16),
+        maxObjectsInGet: UnsignedInt(500),
+        maxObjectsInSet: UnsignedInt(maxObjectsInSet),
+        collationAlgorithms: {CollationIdentifier("i;unicode-casemap")}
+      ),
+      CapabilityIdentifier.jmapMail: MailCapability(
+        maxMailboxesPerEmail: UnsignedInt(10000000),
+        maxSizeAttachmentsPerEmail: UnsignedInt(20000000),
+        emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
+        mayCreateTopLevelMailbox: true
+      ),
+      CapabilityIdentifier.jmapWebSocket: WebSocketCapability(
+        supportsPush: true,
+        url: Uri.parse('ws://domain.com/jmap/ws')
+      ),
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
+      CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
+      CapabilityIdentifier.jmapMdn: MdnCapability(),
+    },
+    {
+      AccountFixtures.aliceAccountId: Account(
+        AccountName('alice@domain.tld'),
+        true,
+        false,
+        {
+          CapabilityIdentifier.jmapSubmission: SubmissionCapability(
+            maxDelayedSend: UnsignedInt(0),
+            submissionExtensions: {}
+          ),
+          CapabilityIdentifier.jmapWebSocket: WebSocketCapability(
+            supportsPush: true,
+            url: Uri.parse('ws://domain.com/jmap/ws')
+          ),
+          CapabilityIdentifier.jmapCore: CoreCapability(
+            maxSizeUpload: UnsignedInt(20971520),
+            maxConcurrentUpload: UnsignedInt(4),
+            maxSizeRequest: UnsignedInt(10000000),
+            maxConcurrentRequests: UnsignedInt(4),
+            maxCallsInRequest: UnsignedInt(16),
+            maxObjectsInGet: UnsignedInt(500),
+            maxObjectsInSet: UnsignedInt(maxObjectsInSet),
+            collationAlgorithms: {CollationIdentifier("i;unicode-casemap")}
+          ),
+          CapabilityIdentifier.jmapMail: MailCapability(
+            maxMailboxesPerEmail: UnsignedInt(10000000),
+            maxSizeAttachmentsPerEmail: UnsignedInt(20000000),
+            emailQuerySortOptions: {"receivedAt", "sentAt", "size", "from", "to", "subject"},
+            mayCreateTopLevelMailbox: true
+          ),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): DefaultCapability(<String, dynamic>{}),
+          CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): DefaultCapability(<String, dynamic>{}),
+          CapabilityIdentifier.jmapVacationResponse: VacationCapability(),
+          CapabilityIdentifier.jmapMdn: MdnCapability()
+        }
+      )
+    },
+    {
+      CapabilityIdentifier.jmapSubmission: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapWebSocket: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapCore: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapMail: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:quota')): AccountFixtures.aliceAccountId,
+      CapabilityIdentifier(Uri.parse('urn:apache:james:params:jmap:mail:shares')): AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapVacationResponse: AccountFixtures.aliceAccountId,
+      CapabilityIdentifier.jmapMdn: AccountFixtures.aliceAccountId,
+    },
+    UserName('alice@domain.tld'),
+    Uri.parse('http://domain.com/jmap'),
+    Uri.parse('http://domain.com/download/{accountId}/{blobId}/?type={type}&name={name}'),
+    Uri.parse('http://domain.com/upload/{accountId}'),
+    Uri.parse('http://domain.com/eventSource?types={types}&closeAfter={closeafter}&ping={ping}'),
+    State('2c9f1b12-b35a-43e6-9af2-0106fb53a943')
+  );
+}
+
+// --- End Fixtures ---
+
+class ManualMockHttpClient implements HttpClient {
+  int postCallCount = 0;
+  final Map<int, dynamic> _responses = {};
+
+  void setResponse(int callIndex, dynamic response) {
+    _responses[callIndex] = response;
+  }
+
+  @override
+  Future<Map<String, dynamic>> post(
+    String url, {
+    dynamic data,
+    Map<String, dynamic>? queryParameters,
+    CancelToken? cancelToken,
+    Options? options,
+    ProgressCallback? onSendProgress,
+    ProgressCallback? onReceiveProgress,
+  }) async {
+    final response = _responses[postCallCount];
+    postCallCount++;
+    if (response is Map<String, dynamic>) {
+       return response;
+    }
+    return <String, dynamic>{};
+  }
+  
+  @override
+  noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
+}
+
+
+class TestBatchSetEmailProcessing
+    with HandleSetErrorMixin, MailAPIMixin, BatchSetEmailProcessingMixin {}
+
+void main() {
+  group('BatchSetEmailProcessingMixin test', () {
+    late ManualMockHttpClient httpClient;
+    late TestBatchSetEmailProcessing testMixin;
+
+    setUp(() {
+      httpClient = ManualMockHttpClient();
+      testMixin = TestBatchSetEmailProcessing();
+      httpClient.postCallCount = 0; // Explicit reset or ensure new instance
+    });
+
+    test(
+        'executeBatchSetEmail should return empty result when emailIds is empty',
+        () async {
+      final result = await testMixin.executeBatchSetEmail(
+        session: SessionFixtures.aliceSession,
+        accountId: AccountFixtures.aliceAccountId,
+        emailIds: [],
+        httpClient: httpClient,
+        onGenerateUpdates: (_) => {},
+      );
+
+      expect(result.emailIdsSuccess, isEmpty);
+      expect(result.mapErrors, isEmpty);
+      expect(httpClient.postCallCount, 0);
+    });
+
+    test(
+        'executeBatchSetEmail should split requests when email count exceeds maxObjects',
+        () async {
+      const maxObjects = 10;
+      final session =
+          SessionFixtures.getAliceSessionWithMaxObjectsInSet(maxObjects);
+      const totalEmails = 25;
+      final List<EmailId> emailIds = List<EmailId>.generate(
+          totalEmails, (index) => EmailId(Id('email_$index')));
+
+      // Mock response for 3 batches (10, 10, 5)
+      // Call 0: 10 success
+      httpClient.setResponse(0, {
+          "sessionState": "session_state",
+          "methodResponses": [
+            [
+              "Email/set",
+              {
+                "accountId": AccountFixtures.aliceAccountId.id.value,
+                "oldState": "oldState",
+                "newState": "newState",
+                "updated": {
+                  for (var i = 0; i < 10; i++) "email_$i": null
+                }
+              },
+              "c0"
+            ]
+          ]
+        });
+        
+      // Call 1: 10 success
+      httpClient.setResponse(1, {
+          "sessionState": "session_state",
+          "methodResponses": [
+            [
+              "Email/set",
+              {
+                  "accountId": AccountFixtures.aliceAccountId.id.value,
+                "oldState": "oldState",
+                "newState": "newState",
+                "updated": {
+                  for (var i = 10; i < 20; i++) "email_$i": null
+                }
+              },
+              "c0"
+            ]
+          ]
+        });
+
+      // Call 2: 5 success
+      httpClient.setResponse(2, {
+          "sessionState": "session_state",
+          "methodResponses": [
+            [
+              "Email/set",
+              {
+                  "accountId": AccountFixtures.aliceAccountId.id.value,
+                "oldState": "oldState",
+                "newState": "newState",
+                "updated": {
+                  for (var i = 20; i < 25; i++) "email_$i": null
+                }
+              },
+              "c0"
+            ]
+          ]
+        });
+
+
+      final result = await testMixin.executeBatchSetEmail(
+        session: session,
+        accountId: AccountFixtures.aliceAccountId,
+        emailIds: emailIds,
+        httpClient: httpClient,
+        onGenerateUpdates: (batchIds) => {
+          for (final id in batchIds) id.id: PatchObject({})
+        },
+      );
+
+      expect(result.emailIdsSuccess.length, totalEmails);
+      expect(result.mapErrors, isEmpty);
+      expect(httpClient.postCallCount, 3);
+    });
+
+    test('executeBatchSetEmail should aggregate errors from batches', () async {
+      const maxObjects = 10;
+      final session =
+          SessionFixtures.getAliceSessionWithMaxObjectsInSet(maxObjects);
+      const totalEmails = 20;
+      final List<EmailId> emailIds = List<EmailId>.generate(
+          totalEmails, (index) => EmailId(Id('email_$index')));
+
+      // Batch 1: Success (0-9)
+      httpClient.setResponse(0, {
+            "sessionState": "session_state",
+            "methodResponses": [
+              [
+                "Email/set",
+                {
+                  "accountId": AccountFixtures.aliceAccountId.id.value,
+                  "oldState": "oldState",
+                  "newState": "newState",
+                  "updated": {
+                    for (var i = 0; i < 10; i++) "email_$i": null
+                  }
+                },
+                "c0"
+              ]
+            ]
+          });
+          
+      // Batch 2: Partial failure (10-19, 19 fails)
+      httpClient.setResponse(1, {
+            "sessionState": "session_state",
+            "methodResponses": [
+              [
+                "Email/set",
+                {
+                  "accountId": AccountFixtures.aliceAccountId.id.value,
+                  "oldState": "oldState",
+                  "newState": "newState",
+                  "updated": {
+                     for (var i = 10; i < 19; i++) "email_$i": null
+                  },
+                  "notUpdated": {
+                    "email_19": {
+                      "type": "someError",
+                      "description": "error description"
+                    }
+                  }
+                },
+                "c0"
+              ]
+            ]
+          });
+
+      final result = await testMixin.executeBatchSetEmail(
+        session: session,
+        accountId: AccountFixtures.aliceAccountId,
+        emailIds: emailIds,
+        httpClient: httpClient,
+        onGenerateUpdates: (batchIds) => {
+          for (final id in batchIds) id.id: PatchObject({})
+        },
+      );
+
+      expect(result.emailIdsSuccess.length, 19);
+      expect(result.mapErrors.length, 1);
+      expect(result.mapErrors[Id('email_19')], isNotNull);
+      expect(httpClient.postCallCount, 2);
+    });
+    test('executeBatchSetEmail should handle null response gracefully from a batch', () async {
+      const maxObjects = 10;
+      final session =
+          SessionFixtures.getAliceSessionWithMaxObjectsInSet(maxObjects);
+      const totalEmails = 20; // 2 batches
+      final List<EmailId> emailIds = List<EmailId>.generate(
+          totalEmails, (index) => EmailId(Id('email_$index')));
+
+      // Batch 1: Success (0-9)
+      httpClient.setResponse(0, {
+        "sessionState": "session_state",
+        "methodResponses": [
+          [
+            "Email/set",
+            {
+              "accountId": AccountFixtures.aliceAccountId.id.value,
+              "oldState": "oldState",
+              "newState": "newState",
+              "updated": {
+                for (var i = 0; i < 10; i++) "email_$i": null
+              }
+            },
+            "c0"
+          ]
+        ]
+      });
+
+      // Batch 2: Null response (simulated by mismatching methodCallId)
+      // Request uses 'c0' (default in tests usually), so we return 'c999'
+      // This causes response.parse('c0') to not find the response and should return null.
+      httpClient.setResponse(1, {
+        "sessionState": "session_state",
+        "methodResponses": [
+          [
+            "Email/set",
+            {
+               "accountId": AccountFixtures.aliceAccountId.id.value,
+               "oldState": "oldState",
+               "newState": "newState",
+               "updated": {}
+            },
+            "c999" // Mismatched ID
+          ]
+        ]
+      });
+
+      final result = await testMixin.executeBatchSetEmail(
+        session: session,
+        accountId: AccountFixtures.aliceAccountId,
+        emailIds: emailIds,
+        httpClient: httpClient,
+        onGenerateUpdates: (batchIds) => {
+          for (final id in batchIds) id.id: PatchObject({})
+        },
+      );
+
+      // Should have processed 10 successfully from first batch
+      expect(result.emailIdsSuccess.length, 10);
+      // And 0 from second batch (silently ignored/logged)
+      expect(result.mapErrors, isEmpty);
+      expect(httpClient.postCallCount, 2);
+    });
+
+    test('executeBatchSetEmail should handle exact match of maxObjectsInSet boundary', () async {
+      const maxObjects = 10;
+      final session =
+          SessionFixtures.getAliceSessionWithMaxObjectsInSet(maxObjects);
+      const totalEmails = 20; // Exactly 2 batches
+      final List<EmailId> emailIds = List<EmailId>.generate(
+          totalEmails, (index) => EmailId(Id('email_$index')));
+
+      // Batch 1: Success
+      httpClient.setResponse(0, {
+        "sessionState": "session_state",
+        "methodResponses": [
+          [
+            "Email/set",
+            {
+              "accountId": AccountFixtures.aliceAccountId.id.value,
+              "oldState": "oldState",
+              "newState": "newState",
+              "updated": {
+                for (var i = 0; i < 10; i++) "email_$i": null
+              }
+            },
+            "c0"
+          ]
+        ]
+      });
+
+      // Batch 2: Success
+      httpClient.setResponse(1, {
+        "sessionState": "session_state",
+        "methodResponses": [
+          [
+            "Email/set",
+            {
+              "accountId": AccountFixtures.aliceAccountId.id.value,
+              "oldState": "oldState",
+              "newState": "newState",
+              "updated": {
+                for (var i = 10; i < 20; i++) "email_$i": null
+              }
+            },
+            "c0"
+          ]
+        ]
+      });
+
+      final result = await testMixin.executeBatchSetEmail(
+        session: session,
+        accountId: AccountFixtures.aliceAccountId,
+        emailIds: emailIds,
+        httpClient: httpClient,
+        onGenerateUpdates: (batchIds) => {
+          for (final id in batchIds) id.id: PatchObject({})
+        },
+      );
+
+      expect(result.emailIdsSuccess.length, 20);
+      expect(result.mapErrors, isEmpty);
+      expect(httpClient.postCallCount, 2);
+    });
+  });
+}