diff --git a/cache/disabledlib.php b/cache/disabledlib.php
index 18cc11eb07d..1e95bbc466c 100644
--- a/cache/disabledlib.php
+++ b/cache/disabledlib.php
@@ -256,10 +256,22 @@ class cache_factory_disabled extends cache_factory {
      * @return cache_config|cache_config_writer
      */
     public function create_config_instance($writer = false) {
+        // We are always going to use the cache_config_disabled class for all regular request.
+        // However if the code has requested the writer then likely something is changing and
+        // we're going to need to interact with the config.php file.
+        // In this case we will still use the cache_config_writer.
         $class = 'cache_config_disabled';
+        if ($writer) {
+            // If the writer was requested then something is changing.
+            $class = 'cache_config_writer';
+        }
         if (!array_key_exists($class, $this->configs)) {
             self::set_state(self::STATE_INITIALISING);
-            $configuration = $class::create_default_configuration();
+            if (!$writer) {
+                $configuration = $class::create_default_configuration();
+            } else {
+                $configuration = false;
+            }
             $this->configs[$class] = new $class;
             $this->configs[$class]->load($configuration);
         }