diff --git a/phpBB/adm/style/acp_ext_catalog.html b/phpBB/adm/style/acp_ext_catalog.html
index 326d6b8bc7..482d8a8bda 100644
--- a/phpBB/adm/style/acp_ext_catalog.html
+++ b/phpBB/adm/style/acp_ext_catalog.html
@@ -6,12 +6,6 @@
 
 <p>{{ lang( 'EXTENSIONS_CATALOG_EXPLAIN') }}</p>
 
-{% if not enabled %}
-<div class="errorbox">
-	{{ lang('EXTENSIONS_COMPOSER_NOT_WRITABLE') }}
-</div>
-{% endif %}
-
 <fieldset class="quick quick-left">
 	<span class="small"><a href="https://www.phpbb.com/go/customise/extensions/3.1" target="_blank">{{ lang('BROWSE_EXTENSIONS_DATABASE') }}</a> &bull; <a href="javascript:phpbb.toggleDisplay('catalog_settings');">{{ lang('SETTINGS') }}</a></span>
 </fieldset>
diff --git a/phpBB/includes/acp/acp_extensions.php b/phpBB/includes/acp/acp_extensions.php
index 1bcbe9f415..6888a00772 100644
--- a/phpBB/includes/acp/acp_extensions.php
+++ b/phpBB/includes/acp/acp_extensions.php
@@ -169,14 +169,21 @@ class acp_extensions
 				$this->list_disabled_exts();
 				$this->list_available_exts();
 
+				/** @var \phpbb\composer\manager $composer_manager */
 				$composer_manager = $phpbb_container->get('ext.composer.manager');
 
+				$managed_packages = [];
+				if ($composer_manager->check_requirements())
+				{
+					$managed_packages = array_keys($composer_manager->get_managed_packages());
+				}
+
 				$this->request->enable_super_globals();
 				$this->template->assign_vars(array(
 					'U_VERSIONCHECK_FORCE' 	=> $this->u_action . '&amp;action=list&amp;versioncheck_force=1',
 					'FORCE_UNSTABLE'		=> $this->config['extension_force_unstable'],
 					'U_ACTION' 				=> $this->u_action,
-					'MANAGED_EXTENSIONS'	=> array_keys($composer_manager->get_managed_packages()),
+					'MANAGED_EXTENSIONS'	=> $managed_packages,
 					'U_CATALOG_ACTION' 		=> append_sid("{$phpbb_admin_path}index.$phpEx", "i=$id&amp;mode=catalog"),
 				));
 				$this->request->disable_super_globals();
@@ -424,6 +431,19 @@ class acp_extensions
 		/** @var \phpbb\extension\manager $extensions_manager */
 		$extensions_manager = $phpbb_container->get('ext.manager');
 
+		if (!$composer_manager->check_requirements())
+		{
+			$this->page_title = 'ACP_EXTENSIONS_CATALOG';
+			$this->tpl_name = 'message_body';
+
+			$this->template->assign_vars([
+				'MESSAGE_TITLE'	=> $language->lang('EXTENSIONS_CATALOG_NOT_AVAILABLE'),
+				'MESSAGE_TEXT'	=> $language->lang('EXTENSIONS_COMPOSER_NOT_WRITABLE'),
+			]);
+
+			return;
+		}
+
 		switch ($action)
 		{
 			case 'install':
@@ -659,7 +679,6 @@ class acp_extensions
 				$this->tpl_name = 'acp_ext_catalog';
 
 				$this->template->assign_vars([
-					'enabled'				=> $manager->check_requirements(),
 					'extensions'			=> $extensions,
 					'managed_extensions'	=> array_keys($managed_packages),
 					'installed_extensions'	=> array_keys($extensions_manager->all_available()),
diff --git a/phpBB/language/en/acp/extensions.php b/phpBB/language/en/acp/extensions.php
index 6f6add6a86..d7c111c3b6 100644
--- a/phpBB/language/en/acp/extensions.php
+++ b/phpBB/language/en/acp/extensions.php
@@ -164,6 +164,7 @@ $lang = array_merge($lang, array(
 	'EXTENSIONS_REMOVED'			=> 'Extensions successfully removed.',
 	'EXTENSIONS_UPDATED'			=> 'Extensions successfully updated.',
 
+	'EXTENSIONS_CATALOG_NOT_AVAILABLE'	=> 'The extensions catalog is not available',
 	'EXTENSIONS_COMPOSER_NOT_WRITABLE'	=> 'In order to use the catalog, the following files and directories must be writable: ext/ vendor-ext/ composer-ext.json and composer-ext.lock',
 
 	'STABILITY_STABLE'	=> 'stable',
diff --git a/phpBB/phpbb/composer/installer.php b/phpBB/phpbb/composer/installer.php
index e684882bfa..205312f9e3 100644
--- a/phpBB/phpbb/composer/installer.php
+++ b/phpBB/phpbb/composer/installer.php
@@ -92,7 +92,7 @@ class installer
 			}
 
 			$this->packagist			= (bool) $config['exts_composer_packagist'];
-			$this->composer_filenam		= $config['exts_composer_json_file'];
+			$this->composer_filename	= $config['exts_composer_json_file'];
 			$this->packages_vendor_dir	= $config['exts_composer_vendor_dir'];
 			$this->minimum_stability	= $config['exts_composer_minimum_stability'];
 		}
@@ -451,7 +451,7 @@ class installer
 	private function get_compatible_versions(array $compatible_packages, ConstraintInterface $core_constraint, $core_stability, $package_name, array $versions)
 	{
 		$core_stability_value = BasePackage::$stabilities[$core_stability];
-		//VersionParser::parseStability($version['version'])
+
 		/** @var \Composer\Package\PackageInterface $version */
 		foreach ($versions as $version)
 		{
diff --git a/phpBB/phpbb/composer/manager.php b/phpBB/phpbb/composer/manager.php
index c9d917e5c9..e040e3e0be 100644
--- a/phpBB/phpbb/composer/manager.php
+++ b/phpBB/phpbb/composer/manager.php
@@ -253,6 +253,7 @@ class manager implements manager_interface
 		if ($this->available_packages === null)
 		{
 			$this->available_packages = $this->cache->get('_composer_' . $this->package_type . '_available');
+
 			if (!$this->available_packages)
 			{
 				$this->available_packages = $this->installer->get_available_packages($this->package_type);