diff --git a/plugin/commands/auto_set_syntax.py b/plugin/commands/auto_set_syntax.py
index 518aa1ff..82fdb46c 100644
--- a/plugin/commands/auto_set_syntax.py
+++ b/plugin/commands/auto_set_syntax.py
@@ -61,6 +61,10 @@ def run_auto_set_syntax_on_view(
     *,
     must_plaintext: bool = False,
 ) -> bool:
+    # multithread guard...
+    if not G.view_snapshot_collection.get_by_view(view):
+        return False
+
     if event is ListenerEvent.EXEC:
         return _assign_syntax_for_exec_output(view, event)