diff --git a/devtools/server/actors/thread.js b/devtools/server/actors/thread.js
index 81510527ef51..82a6d1e55ae4 100644
--- a/devtools/server/actors/thread.js
+++ b/devtools/server/actors/thread.js
@@ -2042,6 +2042,9 @@ const ThreadActor = ActorClassWithSpec(threadSpec, {
     // We use executeSoon because we don't want to block those operations
     // by sending packets in the middle of them.
     DevToolsUtils.executeSoon(() => {
+      if (this.isDestroyed()) {
+        return;
+      }
       this.emit("newSource", {
         source: source.form(),
       });