diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/IWritableIndexManager.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/IWritableIndexManager.java
index bda7cfd95a0..ff7be452df5 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/IWritableIndexManager.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/index/IWritableIndexManager.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006 Wind River Systems, Inc. and others.
+ * Copyright (c) 2006, 2007 Wind River Systems, Inc. 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
@@ -17,6 +17,9 @@ import org.eclipse.core.runtime.CoreException;
 
 public interface IWritableIndexManager extends IIndexManager {
 
+	/**
+	 * Returns a writable index or <code>null</code> if the project does not exist or is not yet
+	 * registered with the pdom manager.
+	 */
 	IWritableIndex getWritableIndex(ICProject project) throws CoreException;
-
 }
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/PDOMRebuildTask.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/PDOMRebuildTask.java
index ddbb9c4b681..aa8ba589a44 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/PDOMRebuildTask.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/PDOMRebuildTask.java
@@ -27,6 +27,7 @@ import org.eclipse.cdt.internal.core.index.IWritableIndexManager;
 import org.eclipse.cdt.internal.core.pdom.IndexerProgress;
 import org.eclipse.cdt.internal.core.pdom.PDOMManager;
 import org.eclipse.cdt.internal.core.pdom.WritablePDOM;
+import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.osgi.util.NLS;
@@ -58,13 +59,19 @@ public class PDOMRebuildTask implements IPDOMIndexerTask {
 		monitor.subTask(NLS.bind(Messages.PDOMIndexerTask_collectingFilesTask, 
 				fIndexer.getProject().getElementName()));
 
-		ICProject project= fIndexer.getProject();
-		if (project.getProject().isOpen()) {
+		ICProject cproject= fIndexer.getProject();
+		IProject project= cproject.getProject();
+		if (project.isOpen() && project.exists()) {
 			try {
-				clearIndex(project);
-				if (!IPDOMManager.ID_NO_INDEXER.equals(fIndexer.getID())) {
-					createDelegate(project, monitor);
+				IWritableIndex index= ((IWritableIndexManager) CCorePlugin.getIndexManager()).getWritableIndex(cproject);
+				if (index != null) {
+					clearIndex(cproject, index);
+					if (!IPDOMManager.ID_NO_INDEXER.equals(fIndexer.getID())) {
+						createDelegate(cproject, monitor);
+					}
 				}
+				// remove task-tags.
+				TodoTaskUpdater.removeTasksFor(project);
 			} catch (CoreException e) {
 				CCorePlugin.log(e);
 			} catch (InterruptedException e) {
@@ -76,8 +83,7 @@ public class PDOMRebuildTask implements IPDOMIndexerTask {
 		}
 	}
 	
-	private void clearIndex(ICProject project) throws CoreException, InterruptedException {
-		IWritableIndex index= ((IWritableIndexManager) CCorePlugin.getIndexManager()).getWritableIndex(project);
+	private void clearIndex(ICProject project, IWritableIndex index) throws CoreException, InterruptedException {
 		// First clear the pdom
 		index.acquireWriteLock(0);
 		try {
@@ -90,8 +96,6 @@ public class PDOMRebuildTask implements IPDOMIndexerTask {
 		finally {
 			index.releaseWriteLock(0);
 		}
-		// remove task-tags.
-		TodoTaskUpdater.removeTasksFor(project.getProject());
 	}
 
 	private synchronized void createDelegate(ICProject project, IProgressMonitor monitor) throws CoreException {
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastIndexerTask.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastIndexerTask.java
index ce8cd92671c..ffb1ee84885 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastIndexerTask.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastIndexerTask.java
@@ -6,8 +6,8 @@
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
- * QNX - Initial API and implementation
- * Markus Schorn (Wind River Systems)
+ *    QNX - Initial API and implementation
+ *    Markus Schorn (Wind River Systems)
  *******************************************************************************/
 
 package org.eclipse.cdt.internal.core.pdom.indexer.fast;
@@ -79,7 +79,9 @@ class PDOMFastIndexerTask extends PDOMIndexerTask implements CallbackHandler {
 				}
 			}
 
-			setupIndexAndReaderFactory();
+			if (!setupIndexAndReaderFactory()) {
+				return;
+			}
 			fIndex.acquireReadLock();
 			try {
 				registerTUsInReaderFactory(sources);
@@ -114,12 +116,16 @@ class PDOMFastIndexerTask extends PDOMIndexerTask implements CallbackHandler {
 		traceEnd(start, fIndex);
 	}
 
-	private void setupIndexAndReaderFactory() throws CoreException {
+	private boolean setupIndexAndReaderFactory() throws CoreException {
 		fIndex= ((IWritableIndexManager) CCorePlugin.getIndexManager()).getWritableIndex(getProject());
+		if (fIndex == null) {
+			return false;
+		}
 		fIndex.resetCacheCounters();
 		fIflCache = new HashMap/*<String,IIndexFileLocation>*/();
 		fCodeReaderFactory = new IndexBasedCodeReaderFactory(getCProject(), fIndex, fIflCache);
 		fCodeReaderFactory.setCallbackHandler(this);
+		return true;
 	}
 
 	private void registerTUsInReaderFactory(Collection tus) throws CoreException {
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullIndexerTask.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullIndexerTask.java
index 04a4482638b..e794cc181ac 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullIndexerTask.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullIndexerTask.java
@@ -6,8 +6,8 @@
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
- * QNX - Initial API and implementation
- * Markus Schorn (Wind River Systems)
+ *    QNX - Initial API and implementation
+ *    Markus Schorn (Wind River Systems)
  *******************************************************************************/
 
 package org.eclipse.cdt.internal.core.pdom.indexer.full;
@@ -86,10 +86,12 @@ class PDOMFullIndexerTask extends PDOMIndexerTask {
 				}
 			}
 
-			setupIndex();
+			if (!setupIndex()) {
+				return;
+			}
 			registerTUsInReaderFactory(sources);
 			registerTUsInReaderFactory(headers);
-								
+
 			Iterator i= fRemoved.iterator();
 			while (i.hasNext()) {
 				if (monitor.isCanceled())
@@ -118,12 +120,16 @@ class PDOMFullIndexerTask extends PDOMIndexerTask {
 		traceEnd(start, fIndex);
 	}
 
-	private void setupIndex() throws CoreException {
+	private boolean setupIndex() throws CoreException {
 		// there is no mechanism to clear dirty files from the cache, so flush it.
 		SavedCodeReaderFactory.getInstance().getCodeReaderCache().flush();	
 
 		fIndex = ((IWritableIndexManager) CCorePlugin.getIndexManager()).getWritableIndex(getProject());
+		if (fIndex == null) {
+			return false;
+		}
 		fIndex.resetCacheCounters();
+		return true;
 	}
 
 	private void registerTUsInReaderFactory(Collection/*<ITranslationUnit>*/ sources)