Index: core/src/main/java/hudson/model/ExecutorList.java
===================================================================
--- core/src/main/java/hudson/model/ExecutorList.java	(revision 0)
+++ core/src/main/java/hudson/model/ExecutorList.java	(revision 0)
@@ -0,0 +1,47 @@
+/*
+ * The MIT License
+ * 
+ * Copyright (c) 2009, Sun Microsystems, Inc., Yahoo! Inc
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package hudson.model;
+
+import java.util.concurrent.CopyOnWriteArrayList;
+
+/**
+ * Specialized list for holding {@link Executor} instances. Ensures that the
+ * executor has been started before it is added to the list.
+ *
+ * @author Mike Dillon
+ */
+public class ExecutorList<E extends Executor> extends CopyOnWriteArrayList<E> {
+    /**
+     * Appends the specified executor to the end of this list after ensuring it
+     * has been started.
+     *
+     * @throws IllegalThreadStateException if the specified executor was dead.
+     */
+    @Override
+    public boolean add(E executor) {
+        if (!executor.isAlive())
+            executor.start();
+        return super.add(executor);
+    }
+}
Index: core/src/main/java/hudson/model/Computer.java
===================================================================
--- core/src/main/java/hudson/model/Computer.java	(revision 23682)
+++ core/src/main/java/hudson/model/Computer.java	(working copy)
@@ -67,7 +67,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Enumeration;
-import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -107,9 +106,9 @@
 @ExportedBean
 public /*transient*/ abstract class Computer extends Actionable implements AccessControlled, ExecutorListener {
 
-    private final CopyOnWriteArrayList<Executor> executors = new CopyOnWriteArrayList<Executor>();
+    private final ExecutorList<Executor> executors = new ExecutorList<Executor>();
     // TODO: 
-    private final CopyOnWriteArrayList<OneOffExecutor> oneOffExecutors = new CopyOnWriteArrayList<OneOffExecutor>();
+    private final ExecutorList<OneOffExecutor> oneOffExecutors = new ExecutorList<OneOffExecutor>();
 
     private int numExecutors;
 
Index: core/src/main/java/hudson/model/Executor.java
===================================================================
--- core/src/main/java/hudson/model/Executor.java	(revision 23682)
+++ core/src/main/java/hudson/model/Executor.java	(working copy)
@@ -74,7 +74,6 @@
         this.owner = owner;
         this.queue = Hudson.getInstance().getQueue();
         this.number = n;
-        start();
     }
 
     @Override