diff --git a/rtgui/thumbimageupdater.cc b/rtgui/thumbimageupdater.cc
index 380f204a8..ed9858ba6 100644
--- a/rtgui/thumbimageupdater.cc
+++ b/rtgui/thumbimageupdater.cc
@@ -70,7 +70,9 @@ public:
 	{
 		int threadCount=1;
 		#ifdef _OPENMP
-		threadCount=omp_get_num_procs();  
+		  #ifndef WIN32	// see Issue 2370
+			threadCount=omp_get_num_procs();
+		  #endif
 		#endif
 		
 		threadPool_=new Glib::ThreadPool(threadCount,0);