diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMDatabase.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMDatabase.java
index bcc2edf3fe3..f1c9d995a72 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMDatabase.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/PDOMDatabase.java
@@ -130,6 +130,9 @@ public class PDOMDatabase implements IPDOM {
 				ILanguage.AST_USE_INDEX |
 				ILanguage.AST_SKIP_INDEXED_HEADERS);
 
+		if (ast == null)
+			return;
+		
 		ast.accept(new ASTVisitor() {
 				{
 					shouldVisitNames = true;