diff --git a/rtengine/improccoordinator.h b/rtengine/improccoordinator.h
index 65eca08c1..6d7999f6e 100644
--- a/rtengine/improccoordinator.h
+++ b/rtengine/improccoordinator.h
@@ -205,6 +205,9 @@ class ImProcCoordinator : public StagedImageProcessor {
         void getSpotWB   (int x, int y, int rectSize, double& temp, double& green);
         void getAutoCrop (double ratio, int &x, int &y, int &w, int &h);
 
+        bool updateTryLock () {return updaterThreadStart.trylock();}
+        void updateUnLock () {updaterThreadStart.unlock();}
+
         void setProgressListener (ProgressListener* pl)  { plistener = pl; }
         void setPreviewImageListener    (PreviewImageListener* il)     {imageListener = il; }
         void setSizeListener     (SizeListener* il)      {sizeListeners.push_back (il); }
diff --git a/rtengine/rtengine.h b/rtengine/rtengine.h
index 430dae767..1a2a78a03 100644
--- a/rtengine/rtengine.h
+++ b/rtengine/rtengine.h
@@ -330,6 +330,10 @@ namespace rtengine {
               * @return the height of the preview image */
             virtual int         getPreviewHeight () =0;
 
+			virtual bool		updateTryLock() = 0;
+
+			virtual void		updateUnLock() = 0;
+
             /** Creates and returns a Crop instance that acts as a window on the image
               * @param editDataProvider pointer to the EditDataProvider that communicates with the EditSubscriber
               * @return a pointer to the Crop object that handles the image data trough its own pipeline */
diff --git a/rtgui/cropwindow.cc b/rtgui/cropwindow.cc
index 4810867af..9689d023d 100755
--- a/rtgui/cropwindow.cc
+++ b/rtgui/cropwindow.cc
@@ -67,7 +67,7 @@ CropWindow::CropWindow (ImageArea* parent, rtengine::StagedImageProcessor* ipc_,
     backColor(options.bgcolor), decorated(true), titleHeight(30),
     sideBorderWidth(3), lowerBorderWidth(3), upperBorderWidth(1), sepWidth(2),
     xpos(30), ypos(30), imgX(0), imgY(0), imgW(1), imgH(1), iarea(parent),
-    cropZoom(0), cropgl(NULL), pmlistener(NULL), observedCropWin(NULL), isFlawnOver(false) {
+    cropZoom(0), cropgl(NULL), pmlistener(NULL), observedCropWin(NULL), ipc(ipc_), isFlawnOver(false) {
 
     Glib::RefPtr<Pango::Context> context = parent->get_pango_context () ;
     Pango::FontDescription fontd = context->get_font_description ();       
@@ -1585,8 +1585,11 @@ void CropWindow::buttonPressed (LWButton* button, int actionCode, void* actionDa
     else if (button==bZoom100) // zoom 100
         zoom11 ();
     else if (button==bClose) {// close
-        deleted = true;
-        iarea->cropWindowClosed (this);
+		if(ipc->updateTryLock()) {
+			deleted = true;
+			iarea->cropWindowClosed (this);
+			ipc->updateUnLock();
+		}
     }
 }
 
diff --git a/rtgui/cropwindow.h b/rtgui/cropwindow.h
index e5c05c0e9..8e331b083 100755
--- a/rtgui/cropwindow.h
+++ b/rtgui/cropwindow.h
@@ -84,6 +84,7 @@ class CropWindow : public LWButtonListener, public CropHandlerListener, public E
         std::list<CropWindowListener*> listeners;
         
         CropWindow* observedCropWin;
+        rtengine::StagedImageProcessor* ipc;
 
         bool onArea                    (CursorArea a, int x, int y);
         void updateCursor              (int x, int y);