diff --git a/XTrap/xtrapdi.c b/XTrap/xtrapdi.c
index 7dd9584a0..55c28a8b9 100644
--- a/XTrap/xtrapdi.c
+++ b/XTrap/xtrapdi.c
@@ -486,7 +486,7 @@ int XETrapCreateEnv(ClientPtr client)
     XETrapEnv *penv = NULL;
     int status = Success;
 
-    if (client->index > MAXCLIENTS)
+    if (client->index >= MAXCLIENTS)
     {
         status = BadImplementation;
     }