1 files changed, 3 insertions, 2 deletions

diff --git a/src/xterm.c b/src/xterm.c
index 4b4eae53be5..0d0a08d078b 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -9103,7 +9103,8 @@ handle_one_xevent (struct x_display_info *dpyinfo,
 
 #if defined HAVE_XSYNC && !defined HAVE_GTK3
             if (event->xclient.data.l[0] == dpyinfo->Xatom_net_wm_sync_request
-                && event->xclient.format == 32)
+                && event->xclient.format == 32
+                && dpyinfo->xsync_supported_p)
               {
                 struct frame *f
                   = x_top_window_to_frame (dpyinfo,
@@ -14784,7 +14785,7 @@ x_free_frame_resources (struct frame *f)
 #endif /* !USE_X_TOOLKIT */
 
 #ifdef HAVE_XSYNC
-      if (FRAME_X_BASIC_COUNTER (f))
+      if (FRAME_X_BASIC_COUNTER (f) != None)
         XSyncDestroyCounter (FRAME_X_DISPLAY (f),
                              FRAME_X_BASIC_COUNTER (f));
 #endif