diff --git a/composer.lock b/composer.lock
index 56d29498e4..b05d491e92 100644
--- a/composer.lock
+++ b/composer.lock
@@ -653,7 +653,7 @@
             "dist": {
                 "type": "path",
                 "url": "core",
-                "reference": "66ca895a3149058381e8f2385541f285235c009f"
+                "reference": "c52542b8ded961942356aae5de373c09f484e4b2"
             },
             "require": {
                 "asm89/stack-cors": "^1.1",
@@ -701,6 +701,7 @@
                 "zendframework/zend-feed": "^2.12"
             },
             "conflict": {
+                "drupal/pathauto": "<1.6",
                 "drush/drush": "<8.1.10"
             },
             "replace": {
diff --git a/core/composer.json b/core/composer.json
index cba9024381..822364cf42 100644
--- a/core/composer.json
+++ b/core/composer.json
@@ -49,6 +49,7 @@
         "pear/archive_tar": "^1.4.8"
     },
     "conflict": {
+        "drupal/pathauto": "<1.6",
         "drush/drush": "<8.1.10"
     },
     "replace": {
diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index c7d4aa4bfc..b58889006b 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -1095,6 +1095,22 @@ function system_requirements($phase) {
       ];
     }
   }
+  if ($phase === 'install' || $phase === 'update') {
+
+    // Prevent installation or update if the pathauto version is less than 1.5.
+    if (\Drupal::moduleHandler()->moduleExists('pathauto')) {
+      $info = system_get_info('module', 'pathauto');
+      if (version_compare($info['version'], '8.x-1.6') < 0) {
+        $requirements['pathauto_module_incompatibility'] = [
+          'title' => t('Pathauto'),
+          'description' => t('The Pathauto module is not compatible with Drupal core version :version. Please update Pathauto to 8.x-1.5 or later.', [
+            ':version' => \Drupal::VERSION,
+          ]),
+          'severity' => REQUIREMENT_ERROR,
+        ];
+      }
+    }
+  }

   return $requirements;
 }