diff --git a/src/nsterm.m b/src/nsterm.m
index bd477a491ff..a6160ed5b2a 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -4098,6 +4098,9 @@ in certain situations (rapid incoming events).
 
   NSTRACE_WHEN (NSTRACE_GROUP_EVENTS, "ns_read_socket");
 
+  if (apploopnr > 0)
+    return -1; /* Already within event loop. */
+
 #ifdef HAVE_NATIVE_FS
   check_native_fs ();
 #endif
@@ -4182,6 +4185,9 @@ in certain situations (rapid incoming events).
 
   NSTRACE_WHEN (NSTRACE_GROUP_EVENTS, "ns_select");
 
+  if (apploopnr > 0)
+    return -1; /* Already within event loop. */
+
 #ifdef HAVE_NATIVE_FS
   check_native_fs ();
 #endif