diff --git a/samples/hellovr_vulkan/hellovr_vulkan_main.cpp b/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
index 07aa2456..33045515 100644
--- a/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
+++ b/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
@@ -868,7 +868,7 @@ bool CMainApplication::BInitVulkanInstance()
 
 			if ( !bFound )
 			{
-				dprintf( "Vulkan missing requested extension '%s'.\n", requiredInstanceExtensions[ nExt ] );
+				dprintf( "Vulkan missing requested extension '%s'.\n", requiredInstanceExtensions[ nExt ].c_str() );
 			}
 		}