diff --git a/src/XSync.c b/src/XSync.c
index 61f8600..492e189 100644
--- a/src/XSync.c
+++ b/src/XSync.c
@@ -290,8 +290,9 @@ XSyncListSystemCounters(Display *dpy, int *n_counters_return)
 	list = (XSyncSystemCounter *)Xmalloc(
 			rep.nCounters * sizeof(XSyncSystemCounter));
 	replylen = rep.length << 2;
-	pWireSysCounter = (xSyncSystemCounter *) Xmalloc ((unsigned) replylen + 1);
-                /* +1 to leave room for last null-terminator */
+	pWireSysCounter = (xSyncSystemCounter *) Xmalloc ((unsigned) replylen +
+							  sizeof(XSyncCounter));
+	/* added sizeof counter to leave room for last counter read-ahead */
 
 	if ((!list) || (!pWireSysCounter))
 	{