diff --git a/src/video/cocoa/wnd_quartz.mm b/src/video/cocoa/wnd_quartz.mm
index 6109c46dd8..dfb59c31f9 100644
--- a/src/video/cocoa/wnd_quartz.mm
+++ b/src/video/cocoa/wnd_quartz.mm
@@ -175,7 +175,8 @@ static CGColorSpaceRef QZ_GetCorrectColorSpace()
 			CMCloseProfile(sysProfile);
 		}
 
-		assert(colorSpace != NULL);
+		if (colorSpace == NULL)
+			error("Could not get system colour space. You might need to recalibrate your monitor.");
 	}
 
 	return colorSpace;