diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastReindex.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastReindex.java
index 86f686742af..f3000b188f7 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastReindex.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/fast/PDOMFastReindex.java
@@ -36,9 +36,9 @@ class PDOMFastReindex extends PDOMFastIndexerJob {
 		try {
 			long start = System.currentTimeMillis();
 			setupIndexAndReaderFactory();
-			registerTUsInReaderFactory(fTUs);
 			
 			clearIndex(index);
+			registerTUsInReaderFactory(fTUs);
 			fFilesToIndex--;
 
 			parseTUs(fTUs, monitor);
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullReindex.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullReindex.java
index 7ea62eea5f7..78cb0bb4d10 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullReindex.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/full/PDOMFullReindex.java
@@ -40,9 +40,8 @@ class PDOMFullReindex extends PDOMFullIndexerJob {
 			long start = System.currentTimeMillis();			
 
 			setupIndexAndReaderFactory();
-			registerTUsInReaderFactory(fTUs);
-			
 			clearIndex(index);
+			registerTUsInReaderFactory(fTUs);			
 			fFilesToIndex--;
 			
 			parseTUs(fTUs, monitor);