diff --git a/src/vs/platform/extensions/common/abstractExtensionService.ts b/src/vs/platform/extensions/common/abstractExtensionService.ts
index bb27a525222..b6b9f4fca70 100644
--- a/src/vs/platform/extensions/common/abstractExtensionService.ts
+++ b/src/vs/platform/extensions/common/abstractExtensionService.ts
@@ -78,6 +78,12 @@ export abstract class AbstractExtensionService<T extends ActivatedExtension> imp
 		});
 	}
 
+	public readExtensions(): TPromise<IExtensionDescription[]> {
+		return this.onReady().then(() => {
+			return this._registry.getAllExtensionDescriptions();
+		});
+	}
+
 	public getExtensionsStatus(): { [id: string]: IExtensionsStatus } {
 		return null;
 	}
diff --git a/src/vs/workbench/api/node/extHost.api.impl.ts b/src/vs/workbench/api/node/extHost.api.impl.ts
index b3bbfb536be..79be650c93a 100644
--- a/src/vs/workbench/api/node/extHost.api.impl.ts
+++ b/src/vs/workbench/api/node/extHost.api.impl.ts
@@ -43,7 +43,7 @@ import * as vscode from 'vscode';
 import * as paths from 'vs/base/common/paths';
 import { realpathSync } from 'fs';
 import { ITelemetryService, ITelemetryInfo } from 'vs/platform/telemetry/common/telemetry';
-import { MainContext, ExtHostContext, InstanceCollection } from './extHost.protocol';
+import { MainContext, ExtHostContext, InstanceCollection, IInitConfiguration } from './extHost.protocol';
 
 
 export interface IExtensionApiFactory {
@@ -53,7 +53,7 @@ export interface IExtensionApiFactory {
 /**
  * This method instantiates and returns the extension API surface
  */
-export function createApiFactory(threadService: IThreadService, extensionService: ExtHostExtensionService, contextService: IWorkspaceContextService, telemetryService: ITelemetryService): IExtensionApiFactory {
+export function createApiFactory(initDataConfiguration: IInitConfiguration, threadService: IThreadService, extensionService: ExtHostExtensionService, contextService: IWorkspaceContextService, telemetryService: ITelemetryService): IExtensionApiFactory {
 
 
 
@@ -64,7 +64,7 @@ export function createApiFactory(threadService: IThreadService, extensionService
 	const extHostDocumentSaveParticipant = col.define(ExtHostContext.ExtHostDocumentSaveParticipant).set<ExtHostDocumentSaveParticipant>(new ExtHostDocumentSaveParticipant(extHostDocuments, threadService.get(MainContext.MainThreadWorkspace)));
 	const extHostEditors = col.define(ExtHostContext.ExtHostEditors).set<ExtHostEditors>(new ExtHostEditors(threadService, extHostDocuments));
 	const extHostCommands = col.define(ExtHostContext.ExtHostCommands).set<ExtHostCommands>(new ExtHostCommands(threadService, extHostEditors, extHostHeapService));
-	const extHostConfiguration = col.define(ExtHostContext.ExtHostConfiguration).set<ExtHostConfiguration>(new ExtHostConfiguration(threadService.get(MainContext.MainThreadConfiguration)));
+	const extHostConfiguration = col.define(ExtHostContext.ExtHostConfiguration).set<ExtHostConfiguration>(new ExtHostConfiguration(threadService.get(MainContext.MainThreadConfiguration), initDataConfiguration));
 	const extHostDiagnostics = col.define(ExtHostContext.ExtHostDiagnostics).set<ExtHostDiagnostics>(new ExtHostDiagnostics(threadService));
 	const languageFeatures = col.define(ExtHostContext.ExtHostLanguageFeatures).set<ExtHostLanguageFeatures>(new ExtHostLanguageFeatures(threadService, extHostDocuments, extHostCommands, extHostHeapService, extHostDiagnostics));
 	const extHostFileSystemEvent = col.define(ExtHostContext.ExtHostFileSystemEventService).set<ExtHostFileSystemEventService>(new ExtHostFileSystemEventService());
diff --git a/src/vs/workbench/api/node/extHost.protocol.ts b/src/vs/workbench/api/node/extHost.protocol.ts
index bc7bf0c2e0a..a7d6157e15b 100644
--- a/src/vs/workbench/api/node/extHost.protocol.ts
+++ b/src/vs/workbench/api/node/extHost.protocol.ts
@@ -43,6 +43,10 @@ export interface IEnvironment {
 	extensionTestsPath: string;
 }
 
+export interface IInitConfiguration {
+	_initConfigurationBrand: void;
+}
+
 export interface IInitData {
 	parentPid: number;
 	environment: IEnvironment;
@@ -50,6 +54,7 @@ export interface IInitData {
 		workspace: IWorkspace;
 	};
 	extensions: IExtensionDescription[];
+	configuration: IInitConfiguration;
 }
 
 export interface InstanceSetter<T> {
@@ -213,7 +218,6 @@ export abstract class MainThreadWorkspaceShape {
 }
 
 export abstract class MainProcessExtensionServiceShape {
-	$onExtensionHostReady(extensionDescriptions: IExtensionDescription[]): TPromise<void> { throw ni(); }
 	$localShowMessage(severity: Severity, msg: string): void { throw ni(); }
 	$onExtensionActivated(extensionId: string): void { throw ni(); }
 	$onExtensionActivationFailed(extensionId: string): void { throw ni(); }
diff --git a/src/vs/workbench/api/node/extHostConfiguration.ts b/src/vs/workbench/api/node/extHostConfiguration.ts
index e2426909469..662c14b0a04 100644
--- a/src/vs/workbench/api/node/extHostConfiguration.ts
+++ b/src/vs/workbench/api/node/extHostConfiguration.ts
@@ -5,7 +5,6 @@
 'use strict';
 
 import { mixin } from 'vs/base/common/objects';
-import { illegalState } from 'vs/base/common/errors';
 import Event, { Emitter } from 'vs/base/common/event';
 import { WorkspaceConfiguration } from 'vscode';
 import { ExtHostConfigurationShape, MainThreadConfigurationShape } from './extHost.protocol';
@@ -14,13 +13,13 @@ import { ConfigurationTarget } from 'vs/workbench/services/configuration/common/
 export class ExtHostConfiguration extends ExtHostConfigurationShape {
 
 	private _proxy: MainThreadConfigurationShape;
-	private _hasConfig: boolean;
 	private _config: any;
 	private _onDidChangeConfiguration = new Emitter<void>();
 
-	constructor(proxy: MainThreadConfigurationShape) {
+	constructor(proxy: MainThreadConfigurationShape, configuration: any) {
 		super();
 		this._proxy = proxy;
+		this._config = configuration;
 	}
 
 	get onDidChangeConfiguration(): Event<void> {
@@ -29,14 +28,10 @@ export class ExtHostConfiguration extends ExtHostConfigurationShape {
 
 	public $acceptConfigurationChanged(config: any) {
 		this._config = config;
-		this._hasConfig = true;
 		this._onDidChangeConfiguration.fire(undefined);
 	}
 
 	public getConfiguration(section?: string): WorkspaceConfiguration {
-		if (!this._hasConfig) {
-			throw illegalState('missing config');
-		}
 
 		const config = section
 			? ExtHostConfiguration._lookUp(section, this._config)
diff --git a/src/vs/workbench/api/node/extHostExtensionService.ts b/src/vs/workbench/api/node/extHostExtensionService.ts
index 8a0f2016c00..5e2c54c7a1f 100644
--- a/src/vs/workbench/api/node/extHostExtensionService.ts
+++ b/src/vs/workbench/api/node/extHostExtensionService.ts
@@ -119,7 +119,7 @@ export class ExtHostExtensionService extends AbstractExtensionService<ExtHostExt
 	 * This class is constructed manually because it is a service, so it doesn't use any ctor injection
 	 */
 	constructor(availableExtensions: IExtensionDescription[], threadService: IThreadService, telemetryService: ITelemetryService, args: { _serviceBrand: any; workspaceStoragePath: string; }) {
-		super(false);
+		super(true);
 		this._registry.registerExtensions(availableExtensions);
 		this._threadService = threadService;
 		this._storage = new ExtHostStorage(threadService);
@@ -186,14 +186,6 @@ export class ExtHostExtensionService extends AbstractExtensionService<ExtHostExt
 		return result;
 	}
 
-	public registrationDone(): void {
-		this._proxy.$onExtensionHostReady(this._registry.getAllExtensionDescriptions()).then(() => {
-			// Wait for the main process to acknowledge its receival of the extensions descriptions
-			// before allowing extensions to be activated
-			this._triggerOnReady();
-		});
-	}
-
 	// -- overwriting AbstractExtensionService
 
 	protected _showMessage(severity: Severity, msg: string): void {
diff --git a/src/vs/workbench/api/node/mainThreadConfiguration.ts b/src/vs/workbench/api/node/mainThreadConfiguration.ts
index b707f4e6a47..39a5c31f124 100644
--- a/src/vs/workbench/api/node/mainThreadConfiguration.ts
+++ b/src/vs/workbench/api/node/mainThreadConfiguration.ts
@@ -25,7 +25,6 @@ export class MainThreadConfiguration extends MainThreadConfigurationShape {
 		this._configurationEditingService = configurationEditingService;
 		const proxy = threadService.get(ExtHostContext.ExtHostConfiguration);
 		this._toDispose = configurationService.onDidUpdateConfiguration(event => proxy.$acceptConfigurationChanged(event.config));
-		proxy.$acceptConfigurationChanged(configurationService.getConfiguration());
 	}
 
 	public dispose(): void {
diff --git a/src/vs/workbench/api/node/mainThreadExtensionService.ts b/src/vs/workbench/api/node/mainThreadExtensionService.ts
index eb2f6954a0c..436d492117e 100644
--- a/src/vs/workbench/api/node/mainThreadExtensionService.ts
+++ b/src/vs/workbench/api/node/mainThreadExtensionService.ts
@@ -7,7 +7,7 @@
 import Severity from 'vs/base/common/severity';
 import { TPromise } from 'vs/base/common/winjs.base';
 import { AbstractExtensionService, ActivatedExtension } from 'vs/platform/extensions/common/abstractExtensionService';
-import { IMessage, IExtensionDescription, IExtensionsStatus } from 'vs/platform/extensions/common/extensions';
+import { IExtensionsRuntimeService, IMessage, IExtensionDescription, IExtensionsStatus } from 'vs/platform/extensions/common/extensions';
 import { ExtensionsRegistry, ExtensionPoint, IExtensionPointUser, ExtensionMessageCollector } from 'vs/platform/extensions/common/extensionsRegistry';
 import { IMessageService } from 'vs/platform/message/common/message';
 import { IThreadService } from 'vs/workbench/services/thread/common/threadService';
@@ -53,7 +53,8 @@ export class MainProcessExtensionService extends AbstractExtensionService<Activa
 	constructor(
 		@IThreadService threadService: IThreadService,
 		@IMessageService messageService: IMessageService,
-		@IEnvironmentService private environmentService: IEnvironmentService
+		@IEnvironmentService private environmentService: IEnvironmentService,
+		@IExtensionsRuntimeService extensionsRuntimeService: IExtensionsRuntimeService
 	) {
 		super(false);
 		this._isDev = !environmentService.isBuilt || !!environmentService.extensionDevelopmentPath;
@@ -62,6 +63,8 @@ export class MainProcessExtensionService extends AbstractExtensionService<Activa
 		this._threadService = threadService;
 		this._proxy = this._threadService.get(ExtHostContext.ExtHostExtensionService);
 		this._extensionsStatus = {};
+
+		extensionsRuntimeService.getExtensions().then((extensionDescriptions) => this._onExtensionDescriptions(extensionDescriptions));
 	}
 
 	private _handleMessage(msg: IMessage) {
@@ -124,7 +127,7 @@ export class MainProcessExtensionService extends AbstractExtensionService<Activa
 
 	// -- called by extension host
 
-	public $onExtensionHostReady(extensionDescriptions: IExtensionDescription[]): TPromise<void> {
+	private _onExtensionDescriptions(extensionDescriptions: IExtensionDescription[]): void {
 		this._registry.registerExtensions(extensionDescriptions);
 
 		let availableExtensions = this._registry.getAllExtensionDescriptions();
@@ -135,7 +138,6 @@ export class MainProcessExtensionService extends AbstractExtensionService<Activa
 		}
 
 		this._triggerOnReady();
-		return;
 	}
 
 	private _handleExtensionPoint<T>(extensionPoint: ExtensionPoint<T>, availableExtensions: IExtensionDescription[]): void {
diff --git a/src/vs/workbench/electron-browser/shell.ts b/src/vs/workbench/electron-browser/shell.ts
index 258ffbab5d3..429b4b21bc3 100644
--- a/src/vs/workbench/electron-browser/shell.ts
+++ b/src/vs/workbench/electron-browser/shell.ts
@@ -296,12 +296,13 @@ export class WorkbenchShell {
 		serviceCollection.set(IExtensionsRuntimeService, extensionsRuntimeService);
 		disposables.add(extensionsRuntimeService);
 
-		const extensionHostProcessWorker = this.startExtensionHost(instantiationService);
+		const extensionHostProcessWorker = instantiationService.createInstance(ExtensionHostProcessWorker);
 		this.threadService = instantiationService.createInstance(MainThreadService, extensionHostProcessWorker.messagingProtocol);
 		serviceCollection.set(IThreadService, this.threadService);
 
 		const extensionService = instantiationService.createInstance(MainProcessExtensionService);
 		serviceCollection.set(IExtensionService, extensionService);
+		extensionHostProcessWorker.start(extensionService);
 
 		serviceCollection.set(ICommandService, new CommandService(instantiationService, extensionService));
 
@@ -454,12 +455,6 @@ export class WorkbenchShell {
 		this.workbench.layout();
 	}
 
-	private startExtensionHost(instantiationService: InstantiationService): ExtensionHostProcessWorker {
-		const extensionHostProcessWorker: ExtensionHostProcessWorker = <ExtensionHostProcessWorker>instantiationService.createInstance(ExtensionHostProcessWorker);
-		extensionHostProcessWorker.start();
-		return extensionHostProcessWorker;
-	}
-
 	public joinCreation(): TPromise<boolean> {
 		return this.workbench.joinCreation();
 	}
diff --git a/src/vs/workbench/node/extensionHostMain.ts b/src/vs/workbench/node/extensionHostMain.ts
index 29216aec2f9..1cf968a7acc 100644
--- a/src/vs/workbench/node/extensionHostMain.ts
+++ b/src/vs/workbench/node/extensionHostMain.ts
@@ -55,7 +55,7 @@ export class ExtensionHostMain {
 		this._extensionService = new ExtHostExtensionService(initData.extensions, threadService, telemetryService, { _serviceBrand: 'optionalArgs', workspaceStoragePath });
 
 		// Create the ext host API
-		const factory = createApiFactory(threadService, this._extensionService, this._contextService, telemetryService);
+		const factory = createApiFactory(initData.configuration, threadService, this._extensionService, this._contextService, telemetryService);
 		defineAPI(factory, this._extensionService);
 	}
 
@@ -107,7 +107,7 @@ export class ExtensionHostMain {
 	}
 
 	public start(): TPromise<void> {
-		return this.registerExtensions();
+		return this.handleEagerExtensions().then(() => this.handleExtensionTests());
 	}
 
 	public terminate(): void {
@@ -142,11 +142,6 @@ export class ExtensionHostMain {
 		}, 1000);
 	}
 
-	private registerExtensions(): TPromise<void> {
-		this._extensionService.registrationDone();
-		return this.handleEagerExtensions().then(() => this.handleExtensionTests());
-	}
-
 	// Handle "eager" activation extensions
 	private handleEagerExtensions(): TPromise<void> {
 		this._extensionService.activateByEvent('*').then(null, (err) => {
diff --git a/src/vs/workbench/services/extensions/electron-browser/extensionHost.ts b/src/vs/workbench/services/extensions/electron-browser/extensionHost.ts
index 3feb264e282..f2f1b0671d9 100644
--- a/src/vs/workbench/services/extensions/electron-browser/extensionHost.ts
+++ b/src/vs/workbench/services/extensions/electron-browser/extensionHost.ts
@@ -22,11 +22,12 @@ import { ipcRenderer as ipc } from 'electron';
 import { IEnvironmentService } from 'vs/platform/environment/common/environment';
 import { ReloadWindowAction } from 'vs/workbench/electron-browser/actions';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
-import { IExtensionsRuntimeService } from 'vs/platform/extensions/common/extensions';
 import { IMessagePassingProtocol } from 'vs/base/parts/ipc/common/ipc';
 import Event, { Emitter } from 'vs/base/common/event';
 import { createQueuedSender, IQueuedSender } from 'vs/base/node/processes';
-import { IInitData } from 'vs/workbench/api/node/extHost.protocol';
+import { IInitData, IInitConfiguration } from 'vs/workbench/api/node/extHost.protocol';
+import { MainProcessExtensionService } from 'vs/workbench/api/node/mainThreadExtensionService';
+import { IWorkspaceConfigurationService } from 'vs/workbench/services/configuration/common/configuration';
 
 export const EXTENSION_LOG_BROADCAST_CHANNEL = 'vscode:extensionLog';
 export const EXTENSION_ATTACH_BROADCAST_CHANNEL = 'vscode:extensionAttach';
@@ -58,6 +59,8 @@ export class ExtensionHostProcessWorker {
 		return this._onMessage.event;
 	}
 
+	private extensionService: MainProcessExtensionService;
+
 	constructor(
 		@IWorkspaceContextService private contextService: IWorkspaceContextService,
 		@IMessageService private messageService: IMessageService,
@@ -65,7 +68,7 @@ export class ExtensionHostProcessWorker {
 		@ILifecycleService lifecycleService: ILifecycleService,
 		@IInstantiationService private instantiationService: IInstantiationService,
 		@IEnvironmentService private environmentService: IEnvironmentService,
-		@IExtensionsRuntimeService private extensionsRuntimeService: IExtensionsRuntimeService
+		@IWorkspaceConfigurationService private configurationService: IWorkspaceConfigurationService
 	) {
 		// handle extension host lifecycle a bit special when we know we are developing an extension that runs inside
 		this.isExtensionDevelopmentHost = !!environmentService.extensionDevelopmentPath;
@@ -78,7 +81,8 @@ export class ExtensionHostProcessWorker {
 		lifecycleService.onShutdown(() => this.terminate());
 	}
 
-	public start(): void {
+	public start(extensionService: MainProcessExtensionService): void {
+		this.extensionService = extensionService;
 		let opts: any = {
 			env: objects.mixin(objects.clone(process.env), {
 				AMD_ENTRYPOINT: 'vs/workbench/node/extensionHostProcess',
@@ -200,7 +204,7 @@ export class ExtensionHostProcessWorker {
 		if (this.initializeTimer) {
 			window.clearTimeout(this.initializeTimer);
 		}
-		this.extensionsRuntimeService.getExtensions().then(extensionDescriptors => {
+		this.extensionService.readExtensions().then((extensionDescriptions) => {
 			let initData: IInitData = {
 				parentPid: process.pid,
 				environment: {
@@ -213,7 +217,8 @@ export class ExtensionHostProcessWorker {
 				contextService: {
 					workspace: this.contextService.getWorkspace()
 				},
-				extensions: extensionDescriptors
+				extensions: extensionDescriptions,
+				configuration: this.configurationService.getConfiguration<IInitConfiguration>()
 			};
 			this.extensionHostProcessQueuedSender.send(stringify(initData));
 		});
diff --git a/src/vs/workbench/test/node/api/extHostConfiguration.test.ts b/src/vs/workbench/test/node/api/extHostConfiguration.test.ts
index 4eb053a2380..50839cabd00 100644
--- a/src/vs/workbench/test/node/api/extHostConfiguration.test.ts
+++ b/src/vs/workbench/test/node/api/extHostConfiguration.test.ts
@@ -25,15 +25,9 @@ suite('ExtHostConfiguration', function () {
 		if (!shape) {
 			shape = new class extends MainThreadConfigurationShape { };
 		}
-		const result = new ExtHostConfiguration(shape);
-		result.$acceptConfigurationChanged(data);
-		return result;
+		return new ExtHostConfiguration(shape, data);
 	}
 
-	test('check illegal state', function () {
-		assert.throws(() => new ExtHostConfiguration(new class extends MainThreadConfigurationShape { }).getConfiguration('foo'));
-	});
-
 	test('udate / section to key', function () {
 
 		const shape = new RecordingShape();