diff --git a/extensions/debug/CHANGELOG.md b/extensions/debug/CHANGELOG.md
index 9e89b70fee2..602ecda35a1 100644
--- a/extensions/debug/CHANGELOG.md
+++ b/extensions/debug/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 debug extension Change Log
 2.0.1 under development
 -----------------------
 
+- Bug #5402: Debugger was not loading when there were closures, resources or PDO instances in the logged data (samdark)
 - Enh #5600: Allow configuring debug panels in `yii\debug\Module::panels` as panel class name strings (qiangxue)
 
 
diff --git a/extensions/debug/LogTarget.php b/extensions/debug/LogTarget.php
index ab7e42df049..755fdcf825e 100644
--- a/extensions/debug/LogTarget.php
+++ b/extensions/debug/LogTarget.php
@@ -55,12 +55,53 @@ public function export()
             $data[$id] = $panel->save();
         }
         $data['summary'] = $summary;
-        file_put_contents($dataFile, serialize($data));
+        file_put_contents($dataFile, serialize($this->replaceUnserializable($data)));
 
         $indexFile = "$path/index.data";
         $this->updateIndexFile($indexFile, $summary);
     }
 
+    /**
+     * Replacing everything that is not serializable with its text representation
+     *
+     * @param mixed $value
+     * @return mixed
+     */
+    private function replaceUnserializable($value)
+    {
+        if (is_scalar($value) || $value === null) {
+            return $value;
+        }
+
+        if (is_array($value)) {
+            foreach ($value as &$row) {
+                $row = $this->replaceUnserializable($row);
+            }
+            return $value;
+        }
+
+        if ($value instanceof \Closure) {
+            return '\Closure';
+        }
+
+        if (is_resource($value)) {
+            return 'resource';
+        }
+
+        if ($value instanceof \PDO) {
+            return '\PDO';
+        }
+
+        $properties = (new \ReflectionObject($value))->getProperties();
+        foreach ($properties as &$property) {
+            $property->setAccessible(true);
+            $propertyValue = $property->getValue($value);
+            $property->setValue($value, $this->replaceUnserializable($propertyValue));
+        }
+
+        return $value;
+    }
+
     /**
      * Updates index file with summary log data
      *
diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index e603dde84e0..dd3b744508a 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.1 under development
 -----------------------
 
+- Bug #5402: Debugger was not loading when there were closures, resources or PDO instances in the logged data (samdark)
 - Bug #5584: `yii\rbac\DbRbacManager` should not delete items when deleting a rule on a database not supporting cascade update (mdmunir)
 - Bug #5601: Simple conditions in Query::where() and ActiveQuery::where() did not allow `yii\db\Expression` to be used as the value (cebe, stevekr)
 - Bug: Gii console command help information does not contain global options (qiangxue)