diff --git a/rtengine/improccoordinator.cc b/rtengine/improccoordinator.cc
index 8e69febdb..30c42a54a 100644
--- a/rtengine/improccoordinator.cc
+++ b/rtengine/improccoordinator.cc
@@ -20,6 +20,7 @@
 #include <curves.h>
 #include <mytime.h>
 #include <refreshmap.h>
+#include <simpleprocess.h>
 #define CLIPTO(a,b,c) ((a)>b?((a)<c?(a):c):b)
 #define CLIP(a) ((a)<65535 ? (a) : (65535));
 
@@ -561,7 +562,7 @@ void ImProcCoordinator::stopProcessing () {
 
 void ImProcCoordinator::startProcessing () {
 
-    #undef THREAD_PRIORITY_LOW
+    #undef THREAD_PRIORITY_NORMAL
 
     if (!destroying) {
         updaterThreadStart.lock ();
@@ -569,7 +570,11 @@ void ImProcCoordinator::startProcessing () {
             thread = NULL;
             updaterRunning = true;
             updaterThreadStart.unlock ();
-            thread = Glib::Thread::create(sigc::mem_fun(*this, &ImProcCoordinator::process), 0, false, true, Glib::THREAD_PRIORITY_LOW);
+
+            batchThread->yield(); //the running batch should wait other threads to avoid conflict
+            
+            thread = Glib::Thread::create(sigc::mem_fun(*this, &ImProcCoordinator::process), 0, true, true, Glib::THREAD_PRIORITY_NORMAL);
+
         }
         else
             updaterThreadStart.unlock ();
diff --git a/rtengine/simpleprocess.cc b/rtengine/simpleprocess.cc
index 6b01bfe2a..03805bf82 100644
--- a/rtengine/simpleprocess.cc
+++ b/rtengine/simpleprocess.cc
@@ -29,6 +29,9 @@
 
 #undef THREAD_PRIORITY_NORMAL
 
+Glib::Thread *batchThread = NULL;
+Glib::Mutex* qMutex = NULL;
+
 namespace rtengine {
 
 IImage16* processImage (ProcessingJob* pjob, int& errorCode, ProgressListener* pl) {
@@ -210,6 +213,10 @@ IImage16* processImage (ProcessingJob* pjob, int& errorCode, ProgressListener* p
 
 void batchProcessingThread (ProcessingJob* job, BatchProcessingListener* bpl) {
 
+    if (!qMutex)
+        qMutex = new Glib::Mutex ();
+
+    qMutex->lock();
     ProcessingJob* currentJob = job;
     
     while (currentJob) {
@@ -219,12 +226,22 @@ void batchProcessingThread (ProcessingJob* job, BatchProcessingListener* bpl) {
             bpl->error ("Can not load input image.");
         currentJob = bpl->imageReady (img);
     }
+    qMutex->unlock();
 }
 
 void startBatchProcessing (ProcessingJob* job, BatchProcessingListener* bpl) {
 
+  
+
     if (bpl)
-        Glib::Thread::create(sigc::bind(sigc::ptr_fun(batchProcessingThread), job, bpl), 0, false, true, Glib::THREAD_PRIORITY_LOW);
+        batchThread = Glib::Thread::create(sigc::bind(sigc::ptr_fun(batchProcessingThread), job, bpl), 0, true, true, Glib::THREAD_PRIORITY_LOW);
+    
+    if(qMutex)
+    {
+        delete qMutex;
+        qMutex = NULL;
+    }
+
 }
 
 }
diff --git a/rtengine/simpleprocess.h b/rtengine/simpleprocess.h
new file mode 100644
index 000000000..bc0675357
--- /dev/null
+++ b/rtengine/simpleprocess.h
@@ -0,0 +1,25 @@
+/* 
+ * File:   simpleprocess.h
+ * Author: askv
+ *
+ * Created on September 18, 2010, 8:31 PM
+ */
+
+#ifndef SIMPLEPROCESS_H
+#define	SIMPLEPROCESS_H
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+    
+
+
+#ifdef	__cplusplus
+}
+#endif
+
+extern Glib::Thread *batchThread;
+
+#endif	/* SIMPLEPROCESS_H */
+