diff --git a/src/arch/LoadingWindow/LoadingWindow_MacOSX.h b/src/arch/LoadingWindow/LoadingWindow_MacOSX.h
index 23f45ddf1c..3a521a3170 100644
--- a/src/arch/LoadingWindow/LoadingWindow_MacOSX.h
+++ b/src/arch/LoadingWindow/LoadingWindow_MacOSX.h
@@ -11,6 +11,7 @@ public:
 	void SetText( RString str );
 	void SetProgress( const int progress );
 	void SetTotalWork( const int totalWork );
+	void SetIndeterminate( bool indeterminate );
 };
 #define USE_LOADING_WINDOW_MACOSX
 
diff --git a/src/arch/LoadingWindow/LoadingWindow_MacOSX.mm b/src/arch/LoadingWindow/LoadingWindow_MacOSX.mm
index bc6a3cf9dc..63a759113f 100644
--- a/src/arch/LoadingWindow/LoadingWindow_MacOSX.mm
+++ b/src/arch/LoadingWindow/LoadingWindow_MacOSX.mm
@@ -15,6 +15,7 @@
 - (void) setupWindow:(NSImage *)image;
 - (void) setProgress:(NSNumber *)progress;
 - (void) setTotalWork:(NSNumber *)totalWork;
+- (void) setIndeterminate:(NSNumber *)indeterminate;
 @end
 
 @implementation LoadingWindowHelper
@@ -96,6 +97,11 @@
 	[m_ProgressIndicator setMaxValue:[totalWork doubleValue]];
 }
 
+- (void) setIndeterminate:(NSNumber *)indeterminate
+{
+	[m_ProgressIndicator setIndeterminate:(indeterminate > 0 ? YES : NO)];
+}
+
 @end
 
 static LoadingWindowHelper *g_Helper = nil;
@@ -160,6 +166,12 @@ void LoadingWindow_MacOSX::SetTotalWork( const int totalWork )
 	[g_Helper performSelectorOnMainThread:@selector(setTotalWork:) withObject:[NSNumber numberWithDouble:(double)totalWork] waitUntilDone:NO];
 }
 
+void LoadingWindow_MacOSX::SetIndeterminate( bool indeterminate )
+{
+	double tmp = indeterminate ? 1 : 0;
+	[g_Helper performSelectorOnMainThread:@selector(setIndeterminate:) withObject:[NSNumber numberWithDouble:tmp] waitUntilDone:NO];
+}
+
 /*
  * (c) 2003-2006, 2008 Steve Checkoway
  * All rights reserved.