diff --git a/libs/vkd3d/vkd3d_debug.h b/libs/vkd3d/vkd3d_debug.h
index b5ef7de2..e5da92c7 100644
--- a/libs/vkd3d/vkd3d_debug.h
+++ b/libs/vkd3d/vkd3d_debug.h
@@ -62,9 +62,9 @@ const char *debugstr_w(const WCHAR *wstr) DECLSPEC_HIDDEN;
 static inline const char *debugstr_uint64(UINT64 v)
 {
     if ((v >> 32) && sizeof(unsigned long) < sizeof(v))
-        return vkd3d_dbg_sprintf("%lx%08lx", (unsigned long)(v >> 32), (unsigned long)v);
+        return vkd3d_dbg_sprintf("%#lx%08lx", (unsigned long)(v >> 32), (unsigned long)v);
 
-    return vkd3d_dbg_sprintf("%lx", (unsigned long)v);
+    return vkd3d_dbg_sprintf("%#lx", (unsigned long)v);
 }
 
 static inline const char *debugstr_guid(const GUID *guid)