diff --git a/QuickLook.Native/QuickLook.Native32/DOpus.cpp b/QuickLook.Native/QuickLook.Native32/DOpus.cpp
index eb1355e..e004f11 100644
--- a/QuickLook.Native/QuickLook.Native32/DOpus.cpp
+++ b/QuickLook.Native/QuickLook.Native32/DOpus.cpp
@@ -30,7 +30,7 @@
 HWND hMsgWnd;
 HANDLE hGetResultEvent;
 
-PCHAR pXmlBuffer;
+PCHAR pXmlBuffer = nullptr;
 
 void DOpus::GetSelected(PWCHAR buffer)
 {
@@ -72,9 +72,12 @@ void DOpus::GetSelected(PWCHAR buffer)
 
     WaitForSingleObject(hGetResultEvent, 2000);
 
-    ParseXmlBuffer(buffer);
-
-    delete[] pXmlBuffer;
+    if (pXmlBuffer != nullptr)
+    {
+        ParseXmlBuffer(buffer);
+        delete[] pXmlBuffer;
+        pXmlBuffer = nullptr;
+    }
 }
 
 void DOpus::ParseXmlBuffer(PWCHAR buffer)
@@ -88,6 +91,9 @@ void DOpus::ParseXmlBuffer(PWCHAR buffer)
      *         ...
      */
 
+    if (pXmlBuffer == nullptr)
+        return;
+
     using namespace rapidxml;
 
     xml_document<> doc;