diff --git a/.phpunit.result.cache b/.phpunit.result.cache
index fedd05c..ef1019d 100644
--- a/.phpunit.result.cache
+++ b/.phpunit.result.cache
@@ -1 +1 @@
-{"version":2,"defects":{"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_replaces_existing_entry":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_creates_new_entry_when_not_exists":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_returns_false_on_path_traversal":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_completed":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_failed":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_timeout_after_max_attempts":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_requests_generation_and_polls_status":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_generation_failure":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_poll_failure":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_restore_after_fail_removes_new_and_restores_old":8,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_module_id":8,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_part":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_part":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_module_id":7},"times":{"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_replaces_existing_entry":0.016,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_creates_new_entry_when_not_exists":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_returns_false_on_path_traversal":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_completed":0.027,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_failed":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_timeout_after_max_attempts":0.002,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_module_id":0.003,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_part":0.011,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_requests_generation_and_polls_status":0.004,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_generation_failure":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_poll_failure":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_restore_after_fail_removes_new_and_restores_old":0.001,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_requires_authentication":0.048,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_module_id":0.027,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_part":0.01,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_1":0.02,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_negative_1":0.001}}
\ No newline at end of file
+{"version":2,"defects":{"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_replaces_existing_entry":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_creates_new_entry_when_not_exists":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_returns_false_on_path_traversal":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_completed":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_failed":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_timeout_after_max_attempts":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_requests_generation_and_polls_status":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_generation_failure":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_poll_failure":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_restore_after_fail_removes_new_and_restores_old":8,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_module_id":8,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_part":8,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_part":7,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_module_id":7},"times":{"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_replaces_existing_entry":0.017,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_creates_new_entry_when_not_exists":0.002,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_atomic_swap_returns_false_on_path_traversal":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_completed":0.027,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_failed":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_timeout_after_max_attempts":0.002,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_module_id":0.002,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_rejects_invalid_part":0.011,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_requests_generation_and_polls_status":0.003,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_generation_failure":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\UpdatePartActionTest::test_throws_on_poll_failure":0.001,"App\\Containers\\VikonIntegration\\Tests\\Unit\\FilesystemTaskTest::test_restore_after_fail_removes_new_and_restores_old":0.001,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_requires_authentication":0.047,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_module_id":0.021,"App\\Containers\\VikonIntegration\\Tests\\Feature\\UpdatePartTest::test_update_part_validates_part":0.008,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_completed_when_status_is_1":0.025,"App\\Containers\\VikonIntegration\\Tests\\Unit\\PollPartStatusTaskTest::test_returns_failed_when_status_is_negative_1":0}}
\ No newline at end of file
diff --git a/app/Containers/VikonIntegration/Actions/UpdateCoreAction.php b/app/Containers/VikonIntegration/Actions/UpdateCoreAction.php
index 53b502c..37ff512 100644
--- a/app/Containers/VikonIntegration/Actions/UpdateCoreAction.php
+++ b/app/Containers/VikonIntegration/Actions/UpdateCoreAction.php
@@ -28,6 +28,7 @@ class UpdateCoreAction
 
         $this->downloadCore($moduleId, $modulePath, $tempPath, $accessToken);
         $this->syncFromFM($moduleId, $modulePath, $accessToken);
+        $this->cleanupPostSync($modulePath);
 
         File::put($modulePath . '/.vikon', date('Y-m-d H:i:s'));
 
@@ -302,4 +303,34 @@ class UpdateCoreAction
             }
         }
     }
+
+    private function cleanupPostSync(string $modulePath): void
+    {
+        if (!File::isDirectory($modulePath)) {
+            return;
+        }
+
+        $removed = 0;
+
+        // Remove _old and _new directories/files left after successful atomic swap
+        foreach (File::directories($modulePath) as $dir) {
+            $name = basename($dir);
+            if (str_ends_with($name, '_old') || str_ends_with($name, '_new')) {
+                File::deleteDirectory($dir);
+                $removed++;
+            }
+        }
+
+        foreach (File::files($modulePath) as $file) {
+            $name = $file->getFilename();
+            if (str_ends_with($name, '_old') || str_ends_with($name, '_new')) {
+                File::delete($file->getPathname());
+                $removed++;
+            }
+        }
+
+        if ($removed > 0) {
+            Log::info('Vikon: cleaned up post-sync', ['removed' => $removed]);
+        }
+    }
 }
diff --git a/app/Containers/VikonIntegration/Actions/UpdatePartAction.php b/app/Containers/VikonIntegration/Actions/UpdatePartAction.php
index 0641ebc..8a95b32 100644
--- a/app/Containers/VikonIntegration/Actions/UpdatePartAction.php
+++ b/app/Containers/VikonIntegration/Actions/UpdatePartAction.php
@@ -93,8 +93,9 @@ class UpdatePartAction
             // Step 5: Apply
             $syncedCount = $this->applyPart($part, $tempPath, $modulePath, $moduleId, $config);
         } finally {
-            // Step 6: Clean temp
+            // Step 6: Clean temp and post-sync artifacts
             File::deleteDirectory($tempPath);
+            $this->cleanupPostSync($modulePath);
         }
 
         Log::info('Vikon: part update complete', ['module' => $moduleId, 'part' => $part, 'synced' => $syncedCount]);
@@ -195,4 +196,33 @@ class UpdatePartAction
 
         return $synced;
     }
+
+    private function cleanupPostSync(string $modulePath): void
+    {
+        if (!File::isDirectory($modulePath)) {
+            return;
+        }
+
+        $removed = 0;
+
+        foreach (File::directories($modulePath) as $dir) {
+            $name = basename($dir);
+            if (str_ends_with($name, '_old') || str_ends_with($name, '_new')) {
+                File::deleteDirectory($dir);
+                $removed++;
+            }
+        }
+
+        foreach (File::files($modulePath) as $file) {
+            $name = $file->getFilename();
+            if (str_ends_with($name, '_old') || str_ends_with($name, '_new')) {
+                File::delete($file->getPathname());
+                $removed++;
+            }
+        }
+
+        if ($removed > 0) {
+            Log::info('Vikon: cleaned up post-sync', ['removed' => $removed, 'path' => $modulePath]);
+        }
+    }
 }