diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3a3de70..7b4e628 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,17 +10,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Theme list and filtering option on basis of theme name and status
 - Module list and filtering option on basis of module name and status
 - Activation of given theme by themeId
-- Mutations to activate and deactive a module.
+- Mutations to de/activate a module.
+- Prevention of de/activation of certain modules mentioned in modules_blocklist.yaml.
 
 ## [1.1.0] - 2024-07-05
 This is stable release for v1.1.0. No changes have been made since v1.1.0-rc.1.
 
 ## [1.1.0-rc.1] - 2024-05-30
-[.gitignore](.gitignore)
 ### Added
 - PHP 8.2 support
 - Module activation dependency on GraphQL Base module
--  Activate a given  theme by themeId.
 
 ### Changed
 - PHPUnit upgraded to version 10.x
@@ -33,6 +32,7 @@ This is stable release for v1.1.0. No changes have been made since v1.1.0-rc.1.
 
 - Initial release
 
+[1.2.0]: https://github.com/OXID-eSales/graphql-configuration-access/compare/v1.1.0...v1.2.0
 [1.1.0]: https://github.com/OXID-eSales/graphql-configuration-access/compare/v1.1.0-rc.1...v1.1.0
 [1.1.0-rc.1]: https://github.com/OXID-eSales/graphql-configuration-access/compare/v1.0.0...v1.1.0-rc.1
 [1.0.0]: https://github.com/OXID-eSales/graphql-configuration-access/releases/tag/v1.0.0
diff --git a/README.md b/README.md
index fa08a17..0d4aa83 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,12 @@ $ vendor/bin/oe-console oe:module:activate oe_graphql_configuration_access
 
 A good starting point is to check the [How to use section in the GraphQL Base Module](https://github.com/OXID-eSales/graphql-base-module/#how-to-use)
 
+## Blocking modules from de/activation via GraphQL
+
+The file module_blockilst.yaml contains a list of modules which are necessary to handle configurations or de/activate
+modules via GraphQL or should be blocked for de/activation via GraphQL in general. Modules like ``oe_graphql_base`` and
+``oe_graphql_configuration_access`` are listed there.
+
 ## Testing
 
 ### Linting, syntax check, static analysis
diff --git a/module_blocklist.yaml b/module_blocklist.yaml
new file mode 100644
index 0000000..80ae9ad
--- /dev/null
+++ b/module_blocklist.yaml
@@ -0,0 +1,3 @@
+modules:
+  - oe_graphql_base
+  - oe_graphql_configuration_access
diff --git a/src/Module/Exception/ModuleActivationBlockedException.php b/src/Module/Exception/ModuleActivationBlockedException.php
new file mode 100644
index 0000000..a2dc549
--- /dev/null
+++ b/src/Module/Exception/ModuleActivationBlockedException.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Exception;
+
+use OxidEsales\GraphQL\Base\Exception\NotFound;
+
+final class ModuleActivationBlockedException extends NotFound
+{
+    private const EXCEPTION_MESSAGE = 'Module "%s" is in the blocklist and cannot be activated.';
+
+    public function __construct(string $moduleId)
+    {
+        parent::__construct(sprintf(self::EXCEPTION_MESSAGE, $moduleId));
+    }
+}
diff --git a/src/Module/Exception/ModuleActivationException.php b/src/Module/Exception/ModuleActivationException.php
index ccc51f9..2e190b3 100644
--- a/src/Module/Exception/ModuleActivationException.php
+++ b/src/Module/Exception/ModuleActivationException.php
@@ -9,9 +9,9 @@
 
 namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Exception;
 
-use OxidEsales\GraphQL\Base\Exception\NotFound;
+use OxidEsales\GraphQL\Base\Exception\Error;
 
-final class ModuleActivationException extends NotFound
+final class ModuleActivationException extends Error
 {
     private const EXCEPTION_MESSAGE = "An error occurred while activating the module.";
 
diff --git a/src/Module/Exception/ModuleDeactivationBlockedException.php b/src/Module/Exception/ModuleDeactivationBlockedException.php
new file mode 100644
index 0000000..994758f
--- /dev/null
+++ b/src/Module/Exception/ModuleDeactivationBlockedException.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Exception;
+
+use OxidEsales\GraphQL\Base\Exception\NotFound;
+
+final class ModuleDeactivationBlockedException extends NotFound
+{
+    private const EXCEPTION_MESSAGE = 'Module "%s" is in the blocklist and cannot be deactivated.';
+
+    public function __construct(string $moduleId)
+    {
+        parent::__construct(sprintf(self::EXCEPTION_MESSAGE, $moduleId));
+    }
+}
diff --git a/src/Module/Exception/ModuleDeactivationException.php b/src/Module/Exception/ModuleDeactivationException.php
index 553084c..f8839a1 100644
--- a/src/Module/Exception/ModuleDeactivationException.php
+++ b/src/Module/Exception/ModuleDeactivationException.php
@@ -9,9 +9,9 @@
 
 namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Exception;
 
-use OxidEsales\GraphQL\Base\Exception\NotFound;
+use OxidEsales\GraphQL\Base\Exception\Error;
 
-final class ModuleDeactivationException extends NotFound
+final class ModuleDeactivationException extends Error
 {
     private const EXCEPTION_MESSAGE = "An error occurred while deactivating the module.";
 
diff --git a/src/Module/Service/ModuleActivationService.php b/src/Module/Service/ModuleActivationService.php
index f7c78cb..aa0d21b 100644
--- a/src/Module/Service/ModuleActivationService.php
+++ b/src/Module/Service/ModuleActivationService.php
@@ -12,13 +12,16 @@
 use OxidEsales\EshopCommunity\Internal\Framework\Module\Setup\Bridge\ModuleActivationBridgeInterface;
 use OxidEsales\EshopCommunity\Internal\Transition\Utility\ContextInterface;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationException;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationBlockedException;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationBlockedException;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationException;
 
 class ModuleActivationService implements ModuleActivationServiceInterface
 {
     public function __construct(
         private readonly ContextInterface $context,
-        private readonly ModuleActivationBridgeInterface $moduleActivationBridge
+        private readonly ModuleActivationBridgeInterface $moduleActivationBridge,
+        private readonly ModuleBlocklistServiceInterface $moduleBlocklistService
     ) {
     }
 
@@ -27,6 +30,10 @@ public function __construct(
      */
     public function activateModule(string $moduleId): bool
     {
+        if ($this->moduleBlocklistService->isModuleBlocked($moduleId)) {
+            throw new ModuleActivationBlockedException($moduleId);
+        }
+
         $shopId = $this->context->getCurrentShopId();
 
         try {
@@ -43,6 +50,10 @@ public function activateModule(string $moduleId): bool
      */
     public function deactivateModule(string $moduleId): bool
     {
+        if ($this->moduleBlocklistService->isModuleBlocked($moduleId)) {
+            throw new ModuleDeactivationBlockedException($moduleId);
+        }
+
         $shopId = $this->context->getCurrentShopId();
 
         try {
diff --git a/src/Module/Service/ModuleActivationServiceInterface.php b/src/Module/Service/ModuleActivationServiceInterface.php
index 1181e9c..0ae22b9 100644
--- a/src/Module/Service/ModuleActivationServiceInterface.php
+++ b/src/Module/Service/ModuleActivationServiceInterface.php
@@ -9,6 +9,7 @@
 
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationException;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationException;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationBlockedException;
 
 interface ModuleActivationServiceInterface
 {
@@ -19,6 +20,7 @@ public function activateModule(string $moduleId): bool;
 
     /**
      * @throws ModuleDeactivationException
+     * @throws ModuleDeactivationBlockedException
      */
     public function deactivateModule(string $moduleId): bool;
 }
diff --git a/src/Module/Service/ModuleBlocklistService.php b/src/Module/Service/ModuleBlocklistService.php
new file mode 100644
index 0000000..57d9a43
--- /dev/null
+++ b/src/Module/Service/ModuleBlocklistService.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Service;
+
+use OxidEsales\EshopCommunity\Internal\Framework\DIContainer\Dao\ProjectYamlDaoInterface;
+
+class ModuleBlocklistService implements ModuleBlocklistServiceInterface
+{
+    public function __construct(
+        private readonly string $moduleBlocklistPath,
+        private readonly ProjectYamlDaoInterface $projectYamlDao
+    ) {
+    }
+
+    public function isModuleBlocked(string $moduleId): bool
+    {
+        $resolvedPath = dirname(__FILE__) . '/../' . $this->moduleBlocklistPath;
+        $configWrapper = $this->projectYamlDao->loadDIConfigFile($resolvedPath);
+        $blocklistData = $configWrapper->getConfigAsArray();
+
+        return in_array($moduleId, $blocklistData['modules'], true);
+    }
+}
diff --git a/src/Module/Service/ModuleBlocklistServiceInterface.php b/src/Module/Service/ModuleBlocklistServiceInterface.php
new file mode 100644
index 0000000..c86b34b
--- /dev/null
+++ b/src/Module/Service/ModuleBlocklistServiceInterface.php
@@ -0,0 +1,13 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Module\Service;
+
+interface ModuleBlocklistServiceInterface
+{
+    public function isModuleBlocked(string $moduleId): bool;
+}
diff --git a/src/Module/services.yaml b/src/Module/services.yaml
index ef62134..504dd14 100644
--- a/src/Module/services.yaml
+++ b/src/Module/services.yaml
@@ -1,3 +1,6 @@
+parameters:
+  oxidesales.graphqlconfigurationaccess.modules_block_list_path: '../../module_blocklist.yaml'
+
 services:
   _defaults:
     public: false
@@ -21,3 +24,8 @@ services:
 
   OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleActivationServiceInterface:
     class: OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleActivationService
+
+  OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistServiceInterface:
+    class: OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistService
+    arguments:
+      $moduleBlocklistPath: '%oxidesales.graphqlconfigurationaccess.modules_block_list_path%'
diff --git a/src/Theme/Controller/ThemeSwitchController.php b/src/Theme/Controller/ThemeSwitchController.php
index 8b6d9d4..d00a5f7 100644
--- a/src/Theme/Controller/ThemeSwitchController.php
+++ b/src/Theme/Controller/ThemeSwitchController.php
@@ -23,14 +23,14 @@ public function __construct(
 
     /**
      * Mutation of Configuration Access Module
-     * @param string $identifier
+     * @param string $themeId
      * @return bool
      */
     #[Mutation]
     #[Logged]
     #[Right('CHANGE_CONFIGURATION')]
-    public function switchTheme(string $identifier): bool
+    public function switchTheme(string $themeId): bool
     {
-        return $this->themeSwitchService->switchTheme($identifier);
+        return $this->themeSwitchService->switchTheme($themeId);
     }
 }
diff --git a/src/Theme/DataType/ThemeDataType.php b/src/Theme/DataType/ThemeDataType.php
index 77f37c6..07cda0f 100644
--- a/src/Theme/DataType/ThemeDataType.php
+++ b/src/Theme/DataType/ThemeDataType.php
@@ -15,13 +15,4 @@
 #[Type]
 class ThemeDataType extends AbstractComponentDataType implements ThemeDataTypeInterface
 {
-    public function __construct(
-        string $id,
-        string $title,
-        string $version,
-        string $description,
-        bool $active
-    ) {
-        parent::__construct($id, $title, $version, $description, $active);
-    }
 }
diff --git a/src/Theme/Infrastructure/ThemeSwitchInfrastructure.php b/src/Theme/Infrastructure/ThemeSwitchInfrastructure.php
index 1386c00..87efcc4 100644
--- a/src/Theme/Infrastructure/ThemeSwitchInfrastructure.php
+++ b/src/Theme/Infrastructure/ThemeSwitchInfrastructure.php
@@ -21,11 +21,11 @@ public function __construct(
     ) {
     }
 
-    public function switchTheme(string $identifier): bool
+    public function switchTheme(string $themeId): bool
     {
         try {
             $coreThemeService = $this->coreThemeFactory->create();
-            if (!$coreThemeService->load($identifier)) {
+            if (!$coreThemeService->load($themeId)) {
                 throw new ThemeActivationException(self::THEME_NOT_EXIST);
             }
             $coreThemeService->activate();
diff --git a/src/Theme/Infrastructure/ThemeSwitchInfrastructureInterface.php b/src/Theme/Infrastructure/ThemeSwitchInfrastructureInterface.php
index f27daa0..6f782ed 100644
--- a/src/Theme/Infrastructure/ThemeSwitchInfrastructureInterface.php
+++ b/src/Theme/Infrastructure/ThemeSwitchInfrastructureInterface.php
@@ -14,5 +14,5 @@ interface ThemeSwitchInfrastructureInterface
     /**
      *@throws ThemeActivationException
      */
-    public function switchTheme(string $identifier): bool;
+    public function switchTheme(string $themeId): bool;
 }
diff --git a/src/Theme/Service/ThemeSwitchService.php b/src/Theme/Service/ThemeSwitchService.php
index da6a065..ba742b1 100644
--- a/src/Theme/Service/ThemeSwitchService.php
+++ b/src/Theme/Service/ThemeSwitchService.php
@@ -17,8 +17,8 @@ public function __construct(
         private readonly ThemeSwitchInfrastructureInterface $themeSwitchInfrastructure
     ) {
     }
-    public function switchTheme(string $identifier): bool
+    public function switchTheme(string $themeId): bool
     {
-        return $this->themeSwitchInfrastructure->switchTheme(identifier: $identifier);
+        return $this->themeSwitchInfrastructure->switchTheme(themeId: $themeId);
     }
 }
diff --git a/src/Theme/Service/ThemeSwitchServiceInterface.php b/src/Theme/Service/ThemeSwitchServiceInterface.php
index 041a7ca..3cfb462 100644
--- a/src/Theme/Service/ThemeSwitchServiceInterface.php
+++ b/src/Theme/Service/ThemeSwitchServiceInterface.php
@@ -9,5 +9,5 @@
 
 interface ThemeSwitchServiceInterface
 {
-    public function switchTheme(string $identifier): bool;
+    public function switchTheme(string $themeId): bool;
 }
diff --git a/tests/Codeception/Acceptance/Module/ModuleSettingBaseCest.php b/tests/Codeception/Acceptance/Module/ModuleSettingBaseCest.php
index 2991ac6..cbb63cf 100644
--- a/tests/Codeception/Acceptance/Module/ModuleSettingBaseCest.php
+++ b/tests/Codeception/Acceptance/Module/ModuleSettingBaseCest.php
@@ -96,6 +96,8 @@ protected function removeConfiguration(string $moduleId): void
     {
         $shopConfiguration = $this->getShopConfiguration();
         $shopConfiguration->deleteModuleConfiguration($moduleId);
+        $shopConfigurationDao = $this->getShopConfigurationDao();
+        $shopConfigurationDao->save($shopConfiguration, 1);
     }
 
     protected function getShopConfigurationDao(): ShopConfigurationDao
diff --git a/tests/Codeception/Acceptance/Module/ModuleSwitchCest.php b/tests/Codeception/Acceptance/Module/ModuleSwitchCest.php
new file mode 100644
index 0000000..f4b1d61
--- /dev/null
+++ b/tests/Codeception/Acceptance/Module/ModuleSwitchCest.php
@@ -0,0 +1,60 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Codeception\Acceptance\Module;
+
+use Codeception\Attribute\DataProvider;
+use OxidEsales\GraphQL\ConfigurationAccess\Tests\Codeception\AcceptanceTester;
+
+/**
+ * @group module_switch
+ * @group theme_switch
+ * @group setting_access
+ * @group oe_graphql_configuration_access
+ */
+final class ModuleSwitchCest extends ModuleSettingBaseCest
+{
+    #[DataProvider('moduleSwitchDataProvider')]
+    public function testModuleSwitchAuthorized(AcceptanceTester $I, \Codeception\Example $example): void
+    {
+        $I->login($this->getAdminUsername(), $this->getAdminPassword());
+
+        $result = $this->runModuleMutation(
+            I: $I,
+            queryName: $example['queryName'],
+            field: $example['field']
+        );
+
+        $I->assertArrayNotHasKey('errors', $result);
+        $response = $result['data'][$example['queryName']];
+        $I->assertTrue($response);
+    }
+
+    private function runModuleMutation(
+        AcceptanceTester $I,
+        string $queryName,
+        string $field
+    ): array {
+        $I->login($this->getAdminUsername(), $this->getAdminPassword());
+        $I->sendGQLQuery(
+            'mutation {
+			  		' . $queryName . '(' . $field . ': "' . self::TEST_MODULE_ID . '")
+				}'
+        );
+
+        $I->seeResponseIsJson();
+        return $I->grabJsonResponseAsArray();
+    }
+
+    protected function moduleSwitchDataProvider(): \Generator
+    {
+        yield ['queryName' => 'activateModule', 'field' => 'moduleId'];
+        yield ['queryName' => 'deactivateModule', 'field' => 'moduleId'];
+    }
+}
diff --git a/tests/Codeception/Acceptance/Theme/ThemeSwitchCest.php b/tests/Codeception/Acceptance/Theme/ThemeSwitchCest.php
index 89b3c10..b15f3d3 100644
--- a/tests/Codeception/Acceptance/Theme/ThemeSwitchCest.php
+++ b/tests/Codeception/Acceptance/Theme/ThemeSwitchCest.php
@@ -34,7 +34,7 @@ private function runThemeSwitchMutation(AcceptanceTester $I): array
 
         $I->sendGQLQuery(
             'mutation switchThemeCest{
-			  		switchTheme(identifier: "' . $themeId . '")
+			  		switchTheme(themeId: "' . $themeId . '")
 				}'
         );
 
diff --git a/tests/Integration/Service/ModuleBlockListServiceTest.php b/tests/Integration/Service/ModuleBlockListServiceTest.php
new file mode 100644
index 0000000..9027215
--- /dev/null
+++ b/tests/Integration/Service/ModuleBlockListServiceTest.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Integration\Infrastructure;
+
+use OxidEsales\EshopCommunity\Internal\Framework\DIContainer\Dao\ProjectYamlDaoInterface;
+use OxidEsales\EshopCommunity\Tests\Integration\IntegrationTestCase;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistService;
+use Symfony\Component\Yaml\Yaml;
+
+class ModuleBlockListServiceTest extends IntegrationTestCase
+{
+    public function testLoadYamlList(): void
+    {
+        $moduleServices = Yaml::parseFile(dirname(__FILE__) . '/../../../src/Module/services.yaml');
+        $blockedListYamlPathParameterName = 'oxidesales.graphqlconfigurationaccess.modules_block_list_path';
+        $blockedListYamlPath = $moduleServices['parameters'][$blockedListYamlPathParameterName];
+
+        $sut = new ModuleBlocklistService(
+            moduleBlocklistPath: $blockedListYamlPath,
+            projectYamlDao: $this->get(ProjectYamlDaoInterface::class)
+        );
+
+        $this->assertTrue($sut->isModuleBlocked('oe_graphql_base'));
+        $this->assertTrue($sut->isModuleBlocked('oe_graphql_configuration_access'));
+    }
+}
diff --git a/tests/Unit/Module/Exception/ModuleActivationBlockedExceptionTest.php b/tests/Unit/Module/Exception/ModuleActivationBlockedExceptionTest.php
new file mode 100644
index 0000000..2275215
--- /dev/null
+++ b/tests/Unit/Module/Exception/ModuleActivationBlockedExceptionTest.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\Module\Exception;
+
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationBlockedException;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationBlockedException
+ */
+final class ModuleActivationBlockedExceptionTest extends TestCase
+{
+    public function testException(): void
+    {
+        $moduleId = uniqid();
+        $exception = new ModuleActivationBlockedException($moduleId);
+
+        $this->assertInstanceOf(ModuleActivationBlockedException::class, $exception);
+        $this->assertSame(
+            sprintf('Module "%s" is in the blocklist and cannot be activated.', $moduleId),
+            $exception->getMessage()
+        );
+    }
+}
diff --git a/tests/Unit/Module/Exception/ModuleActivationExceptionTest.php b/tests/Unit/Module/Exception/ModuleActivationExceptionTest.php
index ca9f973..554366e 100644
--- a/tests/Unit/Module/Exception/ModuleActivationExceptionTest.php
+++ b/tests/Unit/Module/Exception/ModuleActivationExceptionTest.php
@@ -10,7 +10,6 @@
 namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\Module\Exception;
 
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationException;
-use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationException;
 use PHPUnit\Framework\TestCase;
 
 /**
@@ -18,7 +17,7 @@
  */
 final class ModuleActivationExceptionTest extends TestCase
 {
-    public function testActivationException(): void
+    public function testException(): void
     {
         $exception = new ModuleActivationException();
 
diff --git a/tests/Unit/Module/Exception/ModuleDeactivationBlockedExceptionTest.php b/tests/Unit/Module/Exception/ModuleDeactivationBlockedExceptionTest.php
new file mode 100644
index 0000000..fc08ba7
--- /dev/null
+++ b/tests/Unit/Module/Exception/ModuleDeactivationBlockedExceptionTest.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\Module\Exception;
+
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationBlockedException;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationBlockedException
+ */
+final class ModuleDeactivationBlockedExceptionTest extends TestCase
+{
+    public function testException(): void
+    {
+        $moduleId = uniqid();
+        $exception = new ModuleDeactivationBlockedException($moduleId);
+
+        $this->assertInstanceOf(ModuleDeactivationBlockedException::class, $exception);
+        $this->assertSame(
+            sprintf('Module "%s" is in the blocklist and cannot be deactivated.', $moduleId),
+            $exception->getMessage()
+        );
+    }
+}
diff --git a/tests/Unit/Module/Exception/ModuleDeactivationExceptionTest.php b/tests/Unit/Module/Exception/ModuleDeactivationExceptionTest.php
index fed0a35..0a7d536 100644
--- a/tests/Unit/Module/Exception/ModuleDeactivationExceptionTest.php
+++ b/tests/Unit/Module/Exception/ModuleDeactivationExceptionTest.php
@@ -17,7 +17,7 @@
  */
 final class ModuleDeactivationExceptionTest extends TestCase
 {
-    public function testDeactivationException(): void
+    public function testException(): void
     {
         $exception = new ModuleDeactivationException();
 
diff --git a/tests/Unit/Module/Service/ModuleListInfrastructureTest.php b/tests/Unit/Module/Infrastructure/ModuleListInfrastructureTest.php
similarity index 93%
rename from tests/Unit/Module/Service/ModuleListInfrastructureTest.php
rename to tests/Unit/Module/Infrastructure/ModuleListInfrastructureTest.php
index f7d3a83..c13d780 100644
--- a/tests/Unit/Module/Service/ModuleListInfrastructureTest.php
+++ b/tests/Unit/Module/Infrastructure/ModuleListInfrastructureTest.php
@@ -11,10 +11,8 @@
 
 use OxidEsales\EshopCommunity\Internal\Framework\Module\Configuration\Bridge\ShopConfigurationDaoBridgeInterface;
 use OxidEsales\EshopCommunity\Internal\Framework\Module\Configuration\DataObject\ShopConfiguration;
-use OxidEsales\GraphQL\ConfigurationAccess\Module\DataType\ModuleDataTypeFactoryInterface;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Infrastructure\ModuleListInfrastructure;
 use OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\UnitTestCase;
-use OxidEsales\GraphQL\ConfigurationAccess\Module\DataType\ModuleDataTypeInterface;
 use OxidEsales\EshopCommunity\Internal\Framework\Module\Configuration\DataObject\ModuleConfiguration;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModulesNotFoundException;
 
diff --git a/tests/Unit/Module/Service/ModuleActivationsServiceTest.php b/tests/Unit/Module/Service/ModuleActivationsServiceTest.php
index 68a2e2e..f5a8b14 100644
--- a/tests/Unit/Module/Service/ModuleActivationsServiceTest.php
+++ b/tests/Unit/Module/Service/ModuleActivationsServiceTest.php
@@ -12,8 +12,11 @@
 use OxidEsales\EshopCommunity\Internal\Transition\Utility\ContextInterface;
 use OxidEsales\EshopCommunity\Internal\Framework\Module\Setup\Bridge\ModuleActivationBridgeInterface;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationException;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleActivationBlockedException;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationBlockedException;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Exception\ModuleDeactivationException;
 use OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleActivationService;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistServiceInterface;
 use OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\UnitTestCase;
 
 /**
@@ -24,7 +27,7 @@ class ModuleActivationsServiceTest extends UnitTestCase
     /**
      * @dataProvider activationDataProvider
      */
-    public function testModuleActivationAndDeactivation(
+    public function testModuleActivationAndDeactivationSuccess(
         string $method,
     ): void {
         $shopId = 1;
@@ -34,6 +37,12 @@ public function testModuleActivationAndDeactivation(
             ->method($method)
             ->with($moduleId, $shopId);
 
+        $moduleBlocklistServiceMock = $this->createMock(ModuleBlocklistServiceInterface::class);
+        $moduleBlocklistServiceMock
+            ->method('isModuleBlocked')
+            ->with($moduleId)
+            ->willReturn(false);
+
         $sut = $this->getSut(
             context: $this->getContextMock($shopId),
             moduleActivationBridge: $moduleActivationBridgeMock
@@ -47,7 +56,7 @@ public function testModuleActivationAndDeactivation(
     /**
      * @dataProvider exceptionDataProvider
      */
-    public function testModuleActivationAndDeactivationExceptions(
+    public function testModuleActivationAndDeactivationThrowsExceptions(
         string $method,
         mixed $exceptionClass
     ): void {
@@ -55,17 +64,56 @@ public function testModuleActivationAndDeactivationExceptions(
         $moduleActivationBridgeMock = $this->createMock(ModuleActivationBridgeInterface::class);
         $moduleActivationBridgeMock
             ->method($method)
+            ->with($moduleId, 1)
             ->willThrowException(new \Exception());
 
         $this->expectException($exceptionClass);
 
         $sut = $this->getSut(
+            $this->getContextMock(),
             moduleActivationBridge: $moduleActivationBridgeMock
         );
 
         ($method === 'activate') ? $sut->activateModule($moduleId) : $sut->deactivateModule($moduleId);
     }
 
+    /**
+     * @dataProvider moduleBlockedExceptionDataProvider
+     */
+    public function testModuleActivationAndDeactivationBlockedException(
+        string $method,
+        mixed $exceptionClass
+    ) {
+        $moduleId = uniqid();
+        $moduleBlockListServiceMock = $this->createMock(ModuleBlocklistServiceInterface::class);
+        $moduleBlockListServiceMock
+            ->method('isModuleBlocked')
+            ->with($moduleId)
+            ->willReturn(true);
+
+        $sut = $this->getSut(
+            moduleBlocklistService: $moduleBlockListServiceMock
+        );
+
+        $this->expectException($exceptionClass);
+        ($method === 'activate') ? $sut->activateModule($moduleId) : $sut->deactivateModule($moduleId);
+    }
+
+    public static function moduleBlockedExceptionDataProvider(): \Generator
+    {
+        yield 'test activate module blocked exception' => [
+            'method' => 'activate',
+            'exceptionClass' => ModuleActivationBlockedException::class
+
+        ];
+
+        yield 'test deactivate module blocked exception' => [
+            'method' => 'deactivate',
+            'exceptionClass' => ModuleDeactivationBlockedException::class
+
+        ];
+    }
+
     public static function activationDataProvider(): \Generator
     {
         yield 'test activate module' => [
@@ -94,13 +142,16 @@ public static function exceptionDataProvider(): \Generator
 
     public function getSut(
         ContextInterface $context = null,
-        ModuleActivationBridgeInterface $moduleActivationBridge = null
+        ModuleActivationBridgeInterface $moduleActivationBridge = null,
+        ModuleBlocklistServiceInterface $moduleBlocklistService = null
     ): ModuleActivationService {
         return new ModuleActivationService(
             context: $context
                 ??  $this->createStub(ContextInterface::class),
             moduleActivationBridge: $moduleActivationBridge
-                ??  $this->createStub(ModuleActivationBridgeInterface::class)
+                ??  $this->createStub(ModuleActivationBridgeInterface::class),
+            moduleBlocklistService: $moduleBlocklistService
+                ??  $this->createStub(ModuleBlocklistServiceInterface::class)
         );
     }
 }
diff --git a/tests/Unit/Module/Service/ModuleBlocklistServiceTest.php b/tests/Unit/Module/Service/ModuleBlocklistServiceTest.php
new file mode 100644
index 0000000..8026f29
--- /dev/null
+++ b/tests/Unit/Module/Service/ModuleBlocklistServiceTest.php
@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * Copyright © OXID eSales AG. All rights reserved.
+ * See LICENSE file for license details.
+ */
+
+declare(strict_types=1);
+
+namespace OxidEsales\GraphQL\ConfigurationAccess\Tests\Unit\Module\Service;
+
+use OxidEsales\EshopCommunity\Internal\Framework\DIContainer\Dao\ProjectYamlDaoInterface;
+use OxidEsales\EshopCommunity\Internal\Framework\DIContainer\DataObject\DIConfigWrapper;
+use OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistService;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OxidEsales\GraphQL\ConfigurationAccess\Module\Service\ModuleBlocklistService
+ */
+class ModuleBlocklistServiceTest extends TestCase
+{
+    /**
+     * @dataProvider blockListDataProvider
+     */
+    public function testIsModuleBlocked(
+        string $moduleId,
+        bool $expectedResult
+    ): void {
+        $reflector = new \ReflectionClass(ModuleBlocklistService::class);
+        $classFilePath = pathinfo($reflector->getFileName())['dirname'];
+        $filePath = 'testFilePath.yaml';
+        $expectedData = ['modules' => ['module1', 'module2']];
+
+        $configWrapperMock = $this->createMock(DIConfigWrapper::class);
+        $configWrapperMock
+            ->method('getConfigAsArray')
+            ->willReturn($expectedData);
+
+        $projectYamlDaoMock = $this->createMock(ProjectYamlDaoInterface::class);
+        $projectYamlDaoMock
+            ->method('loadDIConfigFile')
+            ->with($classFilePath . '/../' . $filePath)
+            ->willReturn($configWrapperMock);
+
+        $sut = $this->getSut(moduleBlockListPath: $filePath, projectYamlDao: $projectYamlDaoMock);
+        $actualResult = $sut->isModuleBlocked(moduleId: $moduleId);
+
+        $this->assertSame($expectedResult, $actualResult);
+    }
+
+    public static function blockListDataProvider(): \Generator
+    {
+        yield 'isModuleBlocked returns true if Module is in the BlockList' => [
+            'moduleId' => 'module1',
+            'expectedResult' => true
+        ];
+
+        yield 'isModuleBlocked returns false if Module is not in the BlockList' => [
+            'moduleId' => 'unknownModuleId',
+            'expectedResult' => false
+        ];
+    }
+
+    private function getSut(
+        string $moduleBlockListPath,
+        ProjectYamlDaoInterface $projectYamlDao
+    ): ModuleBlocklistService {
+        return new ModuleBlocklistService(
+            moduleBlocklistPath: $moduleBlockListPath,
+            projectYamlDao: $projectYamlDao
+        );
+    }
+}
diff --git a/tests/Unit/Theme/Controller/ThemeSwitchControllerTest.php b/tests/Unit/Theme/Controller/ThemeSwitchControllerTest.php
index eb6eb9f..9bc7aee 100644
--- a/tests/Unit/Theme/Controller/ThemeSwitchControllerTest.php
+++ b/tests/Unit/Theme/Controller/ThemeSwitchControllerTest.php
@@ -20,17 +20,17 @@ class ThemeSwitchControllerTest extends TestCase
 {
     /** @dataProvider switchThemeProvider */
     public function testSwitchTheme(
-        string $identifier,
+        string $themeId,
         bool $expectedResult
     ): void {
         $themeSwitchServiceMock = $this->createMock(ThemeSwitchServiceInterface::class);
         $themeSwitchServiceMock
             ->method('switchTheme')
-            ->with($identifier)
+            ->with($themeId)
             ->willReturn($expectedResult);
 
         $themeSwitchController = new ThemeSwitchController($themeSwitchServiceMock);
-        $response = $themeSwitchController->switchTheme($identifier);
+        $response = $themeSwitchController->switchTheme($themeId);
 
         $this->assertSame($expectedResult, $response);
     }
@@ -38,12 +38,12 @@ public function testSwitchTheme(
     public static function switchThemeProvider(): \Generator
     {
         yield 'test switch theme successful case' => [
-            'identifier' => 'validThemeId',
+            'themeId' => 'validThemeId',
             'expectedResult' => true
         ];
 
         yield 'test switch theme failure case' => [
-            'identifier' => 'invalidThemeId',
+            'themeId' => 'invalidThemeId',
             'expectedResult' => false
         ];
     }
diff --git a/tests/Unit/Theme/Infrastructure/ThemeSwitchInfrastructureTest.php b/tests/Unit/Theme/Infrastructure/ThemeSwitchInfrastructureTest.php
index 2714167..467fbf7 100644
--- a/tests/Unit/Theme/Infrastructure/ThemeSwitchInfrastructureTest.php
+++ b/tests/Unit/Theme/Infrastructure/ThemeSwitchInfrastructureTest.php
@@ -25,23 +25,23 @@ class ThemeSwitchInfrastructureTest extends TestCase
     private const THEME_NOT_EXIST = "The specified theme doesn't exist.";
     public function testSwitchTheme(): void
     {
-        $identifier = 'apex';
+        $themeId = 'apex';
         $coreThemeMock = $this->createMock(Theme::class);
-        $coreThemeMock->expects($this->once())->method('load')->with($identifier)->willReturn(true);
+        $coreThemeMock->expects($this->once())->method('load')->with($themeId)->willReturn(true);
         $coreThemeMock->expects($this->once())->method('activate');
 
         $coreThemeFactoryMock = $this->getCoreThemeFactoryMock(coreThemeMock: $coreThemeMock);
         $sut = $this->getSut(coreThemeFactory: $coreThemeFactoryMock);
 
-        $serviceResponse = $sut->switchTheme($identifier);
+        $serviceResponse = $sut->switchTheme($themeId);
         $this->assertTrue($serviceResponse);
     }
 
     public function testThemeNotActivatedException(): void
     {
-        $identifier = 'apex';
+        $themeId = 'apex';
         $coreThemeMock = $this->createMock(Theme::class);
-        $coreThemeMock->expects($this->once())->method('load')->with($identifier)->willReturn(true);
+        $coreThemeMock->expects($this->once())->method('load')->with($themeId)->willReturn(true);
         $coreThemeMock->expects($this->once())->method('activate')
             ->will($this->throwException(
                 new StandardException(self::THEME_NOT_ACTIVATED)
@@ -52,7 +52,7 @@ public function testThemeNotActivatedException(): void
 
         $this->expectException(ThemeActivationException::class);
         $this->expectExceptionMessage(self::THEME_NOT_ACTIVATED);
-        $sut->switchTheme($identifier);
+        $sut->switchTheme($themeId);
     }
 
     public function testThemeNotFoundException(): void
diff --git a/tests/Unit/Theme/Service/ThemeSwitchServiceTest.php b/tests/Unit/Theme/Service/ThemeSwitchServiceTest.php
index 02fcab2..70cb8d0 100644
--- a/tests/Unit/Theme/Service/ThemeSwitchServiceTest.php
+++ b/tests/Unit/Theme/Service/ThemeSwitchServiceTest.php
@@ -22,15 +22,15 @@ class ThemeSwitchServiceTest extends TestCase
     public function testSwitchTheme(
         bool $expectedResult
     ): void {
-        $identifier = uniqid();
+        $themeId = uniqid();
         $themeSwitchInfrastructureMock = $this->createMock(ThemeSwitchInfrastructureInterface::class);
         $themeSwitchInfrastructureMock
             ->method('switchTheme')
-            ->with($identifier)
+            ->with($themeId)
             ->willReturn($expectedResult);
 
         $themeSwitchInfrastructure = new ThemeSwitchService($themeSwitchInfrastructureMock);
-        $response = $themeSwitchInfrastructure->switchTheme($identifier);
+        $response = $themeSwitchInfrastructure->switchTheme($themeId);
 
         $this->assertSame($expectedResult, $response);
     }