diff --git a/toolkit/devtools/server/transport.js b/toolkit/devtools/server/transport.js
index 412ddc3ddfc9..19d37ace91e2 100644
--- a/toolkit/devtools/server/transport.js
+++ b/toolkit/devtools/server/transport.js
@@ -92,7 +92,14 @@ DebuggerTransport.prototype = {
 
   onOutputStreamReady:
   makeInfallible(function DT_onOutputStreamReady(aStream) {
-    let written = aStream.write(this._outgoing, this._outgoing.length);
+    let written = 0;
+    try {
+      written = aStream.write(this._outgoing, this._outgoing.length);
+    } catch(e if e.result == Components.results.NS_BASE_STREAM_CLOSED) {
+      dumpn("Connection closed.");
+      this.close();
+      return;
+    }
     this._outgoing = this._outgoing.slice(written);
     this._flushOutgoing();
   }, "DebuggerTransport.prototype.onOutputStreamReady"),