diff --git a/samples/hellovr_vulkan/hellovr_vulkan_main.cpp b/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
index 884962b..c100077 100644
--- a/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
+++ b/samples/hellovr_vulkan/hellovr_vulkan_main.cpp
@@ -896,7 +896,7 @@ 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() );
                        }
                }