diff --git a/src/vs/base/parts/ipc/common/ipc.mp.ts b/src/vs/base/parts/ipc/common/ipc.mp.ts
index 91931de0a326d..c63ce5f5cd957 100644
--- a/src/vs/base/parts/ipc/common/ipc.mp.ts
+++ b/src/vs/base/parts/ipc/common/ipc.mp.ts
@@ -44,12 +44,14 @@ export class Protocol implements IMessagePassingProtocol {
 	readonly onMessage;
 
 	constructor(private port: MessagePort) {
-		this.onMessage = Event.fromDOMEventEmitter<VSBuffer>(this.port, 'message', (e: MessageEvent) => {
-			if (e.data) {
-				return VSBuffer.wrap(e.data);
-			}
-			return VSBuffer.alloc(0);
-		});
+		// A `message` event may carry no (or empty) data (e.g. during
+		// connection teardown). An empty frame is never a valid protocol
+		// message (the smallest valid frame still has a serialized header),
+		// so we must not forward it: doing so makes the channel readers
+		// deserialize an `undefined` header and crash. Filter these out at
+		// the transport boundary instead.
+		const onMessage = Event.fromDOMEventEmitter<VSBuffer>(this.port, 'message', (e: MessageEvent) => e.data ? VSBuffer.wrap(e.data) : VSBuffer.alloc(0));
+		this.onMessage = Event.filter(onMessage, data => data.byteLength > 0);
 		// we must call start() to ensure messages are flowing
 		port.start();
 	}