diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CDataProxy.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CDataProxy.java
index 959fad180c3..6f4c4baaea6 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CDataProxy.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CDataProxy.java
@@ -103,6 +103,11 @@ public abstract class CDataProxy implements ICSettingObject {
 		fId = data.getId();
 		fData = data;
 	}
+	
+	void doClearData(){
+		fData = null;
+		setRescan(true);
+	}
 
 	protected void checkUpdate(boolean write){
 		if((write && !containsWritableData()) 
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/ProxyProvider.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/ProxyProvider.java
index fcae5086369..84f2fcf213b 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/ProxyProvider.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/ProxyProvider.java
@@ -128,6 +128,10 @@ public class ProxyProvider implements IProxyProvider {
 
 	public void invalidateCache() {
 		fProxiesCached = false;
+		CDataProxy[] proxies = fCache.getCachedProxies();
+		for(int i = 0; i < proxies.length; i++){
+			proxies[i].doClearData();
+		}
 	}