diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 3795b00a7e..9a6a5f15c1 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -545,9 +545,7 @@ jobs:
                   New-WebHandler -Name "PHP-FastCGI" -Path "*.php" -Modules FastCgiModule -ScriptProcessor "C:\tools\php\php-cgi.exe" -Verb '*' -ResourceType Either
                   iisreset
                   NET START W3SVC
-                  mkdir "${env:GITHUB_WORKSPACE}\phpBB\cache\test"
-                  mkdir "${env:GITHUB_WORKSPACE}\phpBB\cache\installer"
-                  icacls "${env:GITHUB_WORKSPACE}\phpBB\cache" /grant Users:F /T
+                  icacls "${env:GITHUB_WORKSPACE}\phpBB\cache" /grant "Users:(OI)(CI)F" /T
                   icacls "${env:GITHUB_WORKSPACE}\phpBB\files" /grant Users:F /T
                   icacls "${env:GITHUB_WORKSPACE}\phpBB\store" /grant Users:F /T
                   icacls "${env:GITHUB_WORKSPACE}\phpBB\ext" /grant Users:F /T
diff --git a/tests/functional/extension_global_lang_test.php b/tests/functional/extension_global_lang_test.php
index cf2d9dbf29..85275d73b0 100644
--- a/tests/functional/extension_global_lang_test.php
+++ b/tests/functional/extension_global_lang_test.php
@@ -47,20 +47,10 @@ class phpbb_functional_extension_global_lang_test extends phpbb_functional_test_
 		$this->purge_cache();
 	}
 
-	protected function tearDown(): void
-	{
-		$this->uninstall_ext('foo/bar');
-
-		parent::tearDown();
-	}
-
-	protected static function setup_extensions()
-	{
-		return ['foo/bar'];
-	}
-
 	public function test_load_extension_lang_globally()
 	{
+		$this->phpbb_extension_manager->enable('foo/bar');
+
 		// The board index, which should contain an overwritten translation
 		$crawler = self::request('GET', 'index.php');
 
@@ -69,5 +59,7 @@ class phpbb_functional_extension_global_lang_test extends phpbb_functional_test_
 
 		// language from ext/foo/bar/language/en/foo_global.php
 		$this->assertStringContainsString('Overwritten by foo', $crawler->filter('.skiplink')->text());
+
+		$this->phpbb_extension_manager->purge('foo/bar');
 	}
 }
diff --git a/tests/functional/extension_permission_lang_test.php b/tests/functional/extension_permission_lang_test.php
index 9516e351df..0aad34f28a 100644
--- a/tests/functional/extension_permission_lang_test.php
+++ b/tests/functional/extension_permission_lang_test.php
@@ -39,6 +39,13 @@ class phpbb_functional_extension_permission_lang_test extends phpbb_functional_t
 		self::$helper->restore_original_ext_dir();
 	}
 
+	protected function tearDown(): void
+	{
+		$this->purge_cache();
+
+		parent::tearDown();
+	}
+
 	protected function setUp(): void
 	{
 		parent::setUp();
@@ -76,5 +83,7 @@ class phpbb_functional_extension_permission_lang_test extends phpbb_functional_t
 
 		// language from ext/foo/bar/language/en/permissions_foo.php
 		$this->assertStringContainsString('Can view foobar', $crawler->filter('body')->text());
+
+		$this->phpbb_extension_manager->purge('foo/bar');
 	}
 }
diff --git a/tests/functional/extension_template_event_order_test.php b/tests/functional/extension_template_event_order_test.php
index c931c95bc1..c77cb7b89f 100644
--- a/tests/functional/extension_template_event_order_test.php
+++ b/tests/functional/extension_template_event_order_test.php
@@ -39,6 +39,13 @@ class phpbb_functional_extension_template_event_order_test extends phpbb_functio
 		self::$helper->restore_original_ext_dir();
 	}
 
+	protected function tearDown(): void
+	{
+		$this->purge_cache();
+
+		parent::tearDown();
+	}
+
 	protected function setUp(): void
 	{
 		parent::setUp();