diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Builder.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Builder.java
index a8c589011c3..1310c3a1275 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Builder.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Builder.java
@@ -2326,12 +2326,14 @@ public class Builder extends BuildObject implements IBuilder, IMatchKeyProvider
 	}
 	
 	public Set contributeErrorParsers(Set set){
-		if(set == null)
-			set = new HashSet();
-		
-		String ids[] = getErrorParserList();
-		if(ids.length != 0)
-			set.addAll(Arrays.asList(ids));
+		if(getErrorParserIds() != null){
+			if(set == null)
+				set = new HashSet();
+			
+			String ids[] = getErrorParserList();
+			if(ids.length != 0)
+				set.addAll(Arrays.asList(ids));
+		}
 		return set;
 	}
 
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Configuration.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Configuration.java
index d8b88e54ebb..55969a7765a 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Configuration.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Configuration.java
@@ -23,6 +23,7 @@ import java.util.Vector;
 
 import org.eclipse.cdt.build.core.scannerconfig.ICfgScannerConfigBuilderInfo2Set;
 import org.eclipse.cdt.build.internal.core.scannerconfig.CfgDiscoveredPathManager.PathInfoCache;
+import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.settings.model.CIncludePathEntry;
 import org.eclipse.cdt.core.settings.model.CLibraryPathEntry;
 import org.eclipse.cdt.core.settings.model.CSourceEntry;
@@ -1410,19 +1411,24 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 //		}
 //		return errorParsers;
 		Set set = contributeErrorParsers(null, true);
-		String result[] = new String[set.size()];
-		set.toArray(result);
-		return result;
+		if(set != null){
+			String result[] = new String[set.size()];
+			set.toArray(result);
+			return result;
+		}
+		return CCorePlugin.getDefault().getAllErrorParsersIDs();
 	}
 
 	public Set contributeErrorParsers(Set set, boolean includeChildren) {
 		String parserIDs = getErrorParserIdsAttribute();
-		if(set == null)
-			set = new HashSet();
-		if (parserIDs != null && parserIDs.length() != 0) {
-			StringTokenizer tok = new StringTokenizer(parserIDs, ";"); //$NON-NLS-1$
-			while (tok.hasMoreElements()) {
-				set.add(tok.nextToken());
+		if (parserIDs != null){
+			if(set == null)
+				set = new HashSet();
+			if(parserIDs.length() != 0) {
+				StringTokenizer tok = new StringTokenizer(parserIDs, ";"); //$NON-NLS-1$
+				while (tok.hasMoreElements()) {
+					set.add(tok.nextToken());
+				}
 			}
 		}
 		
@@ -1430,7 +1436,7 @@ public class Configuration extends BuildObject implements IConfiguration, IBuild
 			IResourceInfo[] rcInfos = getResourceInfos();
 			for(int i = 0; i < rcInfos.length; i++){
 				ResourceInfo rcInfo = (ResourceInfo)rcInfos[i];
-				rcInfo.contributeErrorParsers(set);
+				set = rcInfo.contributeErrorParsers(set);
 			}
 		}
 		return set;
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/FolderInfo.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/FolderInfo.java
index 04f5f2313f2..cf3924d9d09 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/FolderInfo.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/FolderInfo.java
@@ -1440,11 +1440,11 @@ public class FolderInfo extends ResourceInfo implements IFolderInfo {
 	}
 
 	public Set contributeErrorParsers(Set set){
-		if(set == null)
-			set = new HashSet();
+//		if(set == null)
+//			set = new HashSet();
 		
 		if(toolChain != null)
-			toolChain.contributeErrorParsers(this, set, true);
+			set = toolChain.contributeErrorParsers(this, set, true);
 		
 		return set;
 	}
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ResourceInfo.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ResourceInfo.java
index 1eacae2c4b6..0d72a91efa1 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ResourceInfo.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ResourceInfo.java
@@ -469,11 +469,11 @@ public abstract class ResourceInfo extends BuildObject implements IResourceInfo
 	public abstract Set contributeErrorParsers(Set set);
 	
 	protected Set contributeErrorParsers(ITool[] tools, Set set){
-		if(set == null)
-			set = new HashSet();
+//		if(set == null)
+//			set = new HashSet();
 		for(int i = 0; i < tools.length; i++){
 			Tool tool = (Tool)tools[i];
-			tool.contributeErrorParsers(set);
+			set = tool.contributeErrorParsers(set);
 		}
 		return set;
 	}
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
index 95ea938f764..bc90f0906ad 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/Tool.java
@@ -1717,12 +1717,13 @@ public class Tool extends HoldsOptions implements ITool, IOptionCategory, IMatch
 	}
 	
 	public Set contributeErrorParsers(Set set){
-		if(set == null)
-			set = new HashSet();
-		
-		String ids[] = getErrorParserList();
-		if(ids.length != 0)
-			set.addAll(Arrays.asList(ids));
+		if(getErrorParserIds() != null){
+			if(set == null)
+				set = new HashSet();
+			String ids[] = getErrorParserList();
+			if(ids.length != 0)
+				set.addAll(Arrays.asList(ids));
+		}
 		return set;
 	}
 
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ToolChain.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ToolChain.java
index 1cdb55f9806..3c37f092c9d 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ToolChain.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/core/ToolChain.java
@@ -1377,24 +1377,25 @@ public class ToolChain extends HoldsOptions implements IToolChain, IBuildPropert
 	}
 	
 	public Set contributeErrorParsers(FolderInfo info, Set set, boolean includeChildren){
-		if(set == null)
-			set = new HashSet();
-		
 		String parserIDs = getErrorParserIdsAttribute();
-		if (parserIDs != null && parserIDs.length() != 0) {
-			StringTokenizer tok = new StringTokenizer(parserIDs, ";"); //$NON-NLS-1$
-			while (tok.hasMoreElements()) {
-				set.add(tok.nextToken());
+		if (parserIDs != null){
+			if(set == null)
+				set = new HashSet();
+			if(parserIDs.length() != 0) {
+				StringTokenizer tok = new StringTokenizer(parserIDs, ";"); //$NON-NLS-1$
+				while (tok.hasMoreElements()) {
+					set.add(tok.nextToken());
+				}
 			}
 		}
 		
 		if(includeChildren){
 			ITool tools[] = info.getFilteredTools();
-			info.contributeErrorParsers(tools, set);
+			set = info.contributeErrorParsers(tools, set);
 			
 			if(info.isRoot()){
 				Builder builder = (Builder)getBuilder();
-				builder.contributeErrorParsers(set);
+				set = builder.contributeErrorParsers(set);
 			}
 		}
 		return set;
diff --git a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ExternalExtensionMacroSupplier.java b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ExternalExtensionMacroSupplier.java
index 46ed2d72717..e54442bebc3 100644
--- a/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ExternalExtensionMacroSupplier.java
+++ b/build/org.eclipse.cdt.managedbuilder.core/src/org/eclipse/cdt/managedbuilder/internal/dataprovider/ExternalExtensionMacroSupplier.java
@@ -215,7 +215,7 @@ public class ExternalExtensionMacroSupplier implements ICdtVariableSupplier{
 		if(macros == null || macros.length == 0)
 			return macros;
 		
-		ICdtVariable filtered[] = new IBuildMacro[macros.length];
+		ICdtVariable filtered[] = new ICdtVariable[macros.length];
 		int filteredNum = 0;
 		for(int i = 0; i < macros.length; i++){
 			ICdtVariable var = macros[i];
diff --git a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CProjectDescriptionManager.java b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CProjectDescriptionManager.java
index 2b57c820410..dc7f23b4170 100644
--- a/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CProjectDescriptionManager.java
+++ b/core/org.eclipse.cdt.core/model/org/eclipse/cdt/internal/core/settings/model/CProjectDescriptionManager.java
@@ -281,11 +281,18 @@ public class CProjectDescriptionManager implements ICProjectDescriptionManager {
 	}
 	
 	public static CProjectDescriptionManager getInstance(){
+		if(fInstance == null)
+			fInstance = getInstanceSynch();
+		return fInstance;
+	}
+	
+	private static synchronized CProjectDescriptionManager getInstanceSynch(){
 		if(fInstance == null)
 			fInstance = new CProjectDescriptionManager();
 		return fInstance;
 	}
 
+
 	public void registerResourceListener() {
 		assert fRcChangeHandler == null;
 		fRcChangeHandler = new ResourceChangeHandler();
diff --git a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CConfigBasedDescriptor.java b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CConfigBasedDescriptor.java
index 0317cfd7453..6dbb2b42c6d 100644
--- a/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CConfigBasedDescriptor.java
+++ b/core/org.eclipse.cdt.core/src/org/eclipse/cdt/internal/core/CConfigBasedDescriptor.java
@@ -304,7 +304,7 @@ public class CConfigBasedDescriptor implements ICDescriptor {
 	}
 
 	public void saveProjectData() throws CoreException {
-		if(CConfigBasedDescriptorManager.getInstance().reconsile(this, fCfgDes.getProjectDescription()))
+		if(CProjectDescriptionManager.getInstance().getDescriptorManager().reconsile(this, fCfgDes.getProjectDescription()))
 			fIsDirty = true;
 		
 		checkApply();