diff --git a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertyList.java b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertyList.java
index dcd2ef48240..67d39821f13 100644
--- a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertyList.java
+++ b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertyList.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2008 IBM Corporation and others.
+ * Copyright (c) 2007, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -8,6 +8,7 @@
  * Contributors:
  * IBM Corporation - initial API and implementation
  * David Dykstal (IBM) - [226561] Add API markup to RSE javadocs for extend / implement
+ * David McKnight (IBM)  -[413000] intermittent RSEDOMExporter NPE
  *******************************************************************************/
 package org.eclipse.rse.core.model;
 
@@ -29,20 +30,26 @@ public class PropertyList extends PropertySet {
 	}
 	
 	public IProperty addProperty(String key, IProperty property) {
-		_keys.remove(key);
-		_keys.add(key);
+		synchronized (_keys){
+			_keys.remove(key);
+			_keys.add(key);
+		}
 		return super.addProperty(key, property);
 	}
 	
 	public IProperty addProperty(String key, String value) {
-		_keys.remove(key);
-		_keys.add(key);
+		synchronized (_keys){
+			_keys.remove(key);
+			_keys.add(key);
+		}
 		return super.addProperty(key, value);
 	}
 	
 	public IProperty addProperty(String key, String value, IPropertyType type) {
-		_keys.remove(key);
-		_keys.add(key);
+		synchronized (_keys){
+			_keys.remove(key);
+			_keys.add(key);
+		}
 		return super.addProperty(key, value, type);
 	}
 	
@@ -51,13 +58,17 @@ public class PropertyList extends PropertySet {
 	}
 	
 	public boolean removeProperty(String key) {
-		_keys.remove(key);
+		synchronized (_keys){
+			_keys.remove(key);
+		}
 		return super.removeProperty(key);
 	}
 	
 	public void setProperties(Map map) {
-		_keys.clear();
-		_keys.addAll(map.keySet());
+		synchronized (_keys){
+			_keys.clear();
+			_keys.addAll(map.keySet());
+		}
 		super.setProperties(map);
 	}
 
diff --git a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertySet.java b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertySet.java
index 7a8903be942..565aa5368fc 100644
--- a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertySet.java
+++ b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/core/model/PropertySet.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2011 IBM Corporation and others.
+ * Copyright (c) 2006, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -16,6 +16,7 @@
  * David McKnight   (IBM)        - [217715] [api] RSE property sets should support nested property sets
  * David Dykstal (IBM) - [226561] Add API markup to RSE javadocs for extend / implement
  * David McKnight   (IBM)        - [334837] Ordering of Library list entries incorrect after migration
+ * David McKnight (IBM)  -[413000] intermittent RSEDOMExporter NPE
  *******************************************************************************/
 
 package org.eclipse.rse.core.model;
@@ -134,7 +135,9 @@ public class PropertySet extends RSEModelObject implements IPropertySet, IRSEMod
 	 * @return The added Property
 	 */
 	public IProperty addProperty(String key, IProperty property) {
-		_properties.put(key, property);
+		synchronized (_properties){
+			_properties.put(key, property);
+		}
 		setDirty(true);
 		return property;
 	}
@@ -157,7 +160,10 @@ public class PropertySet extends RSEModelObject implements IPropertySet, IRSEMod
 	}
 
 	public boolean removeProperty(String key) {
-		Object value = _properties.remove(key);
+		Object value = null;
+		synchronized (_properties){
+			value = _properties.remove(key);
+		}
 		if (value == null) return false;
 		setDirty(true);
 		return true;
diff --git a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/internal/persistence/dom/RSEDOMExporter.java b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/internal/persistence/dom/RSEDOMExporter.java
index 1b48a0f46e6..297ae2df1de 100644
--- a/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/internal/persistence/dom/RSEDOMExporter.java
+++ b/rse/plugins/org.eclipse.rse.core/src/org/eclipse/rse/internal/persistence/dom/RSEDOMExporter.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2008 IBM Corporation and others.
+ * Copyright (c) 2006, 2013 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -20,6 +20,7 @@
  * David Dykstal (IBM) - [189274] provide import and export operations for profiles
  * David Dykstal (IBM) - [232126] persist filter type attribute
  * David McKnight (IBM) - [247011] Process subsystem disappears after restart
+ * David McKnight (IBM) - [413000] intermittent RSEDOMExporter NPE 
  *******************************************************************************/
 
 package org.eclipse.rse.internal.persistence.dom;
@@ -192,12 +193,13 @@ public class RSEDOMExporter implements IRSEDOMExporter {
 		String[] keys = set.getPropertyKeys();
 		for (int k = 0; k < keys.length; k++) {
 			String key = keys[k];
-			String value = set.getPropertyValue(key);
-			IPropertyType type = set.getPropertyType(key);
-			RSEDOMNode propertyNode = new RSEDOMNode(propertySetNode, IRSEDOMConstants.TYPE_PROPERTY, key);
-			propertyNode.addAttribute(IRSEDOMConstants.ATTRIBUTE_TYPE, type.toString());
-			propertyNode.addAttribute(IRSEDOMConstants.ATTRIBUTE_VALUE, value);
-			
+			if (key != null){
+				String value = set.getPropertyValue(key);
+				IPropertyType type = set.getPropertyType(key);
+				RSEDOMNode propertyNode = new RSEDOMNode(propertySetNode, IRSEDOMConstants.TYPE_PROPERTY, key);
+				propertyNode.addAttribute(IRSEDOMConstants.ATTRIBUTE_TYPE, type.toString());
+				propertyNode.addAttribute(IRSEDOMConstants.ATTRIBUTE_VALUE, value);
+			}
 		}
 		// persist nested property sets of property set
 		if (set instanceof IRSEModelObject){