diff --git a/Code/Mantid/Framework/API/src/BoxController.cpp b/Code/Mantid/Framework/API/src/BoxController.cpp
index 110e7bb3b77471e2672c2895d63f18fad005a894..6afd510b72161557206f83586d85dc4ce5475db4 100644
--- a/Code/Mantid/Framework/API/src/BoxController.cpp
+++ b/Code/Mantid/Framework/API/src/BoxController.cpp
@@ -209,7 +209,6 @@ namespace API
     this->m_numMDGridBoxes = splitStringIntoVector<size_t>(s);
 
     this->calcNumSplit();
-    pDoc->release();
   }
   /** function clears the file-backed status of the box controller */ 
    void BoxController::clearFileBacked()