diff --git a/extensions/typescript/src/features/bufferSyncSupport.ts b/extensions/typescript/src/features/bufferSyncSupport.ts
index 89ade4b5e1a19f2df52264f21c639a6916bb7dc6..4225c0c54283e288b318b14e052eed8e64f5c495 100644
--- a/extensions/typescript/src/features/bufferSyncSupport.ts
+++ b/extensions/typescript/src/features/bufferSyncSupport.ts
@@ -5,6 +5,7 @@
 'use strict';
 
 import * as fs from 'fs';
+import * as path from 'path';
 
 import { workspace, TextDocument, TextDocumentChangeEvent, TextDocumentContentChangeEvent, Disposable } from 'vscode';
 import * as Proto from '../protocol';
@@ -78,6 +79,7 @@ export default class BufferSyncSupport {
 
 	private _validate: boolean;
 	private modeIds: Map<boolean>;
+	private extensions: Map<boolean>;
 	private diagnostics: Diagnostics;
 	private disposables: Disposable[] = [];
 	private syncedBuffers: Map<SyncedBuffer>;
@@ -86,11 +88,12 @@ export default class BufferSyncSupport {
 	private pendingDiagnostics: { [key: string]: number; };
 	private diagnosticDelayer: Delayer<any>;
 
-	constructor(client: ITypescriptServiceClient, modeIds: string[], diagnostics: Diagnostics, validate: boolean = true) {
+	constructor(client: ITypescriptServiceClient, modeIds: string[], diagnostics: Diagnostics, extensions: Map<boolean>, validate: boolean = true) {
 		this.client = client;
 		this.modeIds = Object.create(null);
 		modeIds.forEach(modeId => this.modeIds[modeId] = true);
 		this.diagnostics = diagnostics;
+		this.extensions = extensions;
 		this._validate = validate;
 
 		this.pendingDiagnostics = Object.create(null);
@@ -173,7 +176,7 @@ export default class BufferSyncSupport {
 			return;
 		}
 		// If the file still exists on disk keep on validating the file.
-		if (fs.existsSync(filepath)) {
+		if (fs.existsSync(filepath) && this.extensions[path.extname(filepath)]) {
 			this.closedFiles[filepath] = true;
 		} else {
 			// Ensure we don't have the file in the map and clear all errors.
diff --git a/extensions/typescript/src/typescriptMain.ts b/extensions/typescript/src/typescriptMain.ts
index 57e05ea5ac4a3bc69e454c16951ef9840f977ef7..a336d72f4b0b379b9b38775b45d5f089af8182ad 100644
--- a/extensions/typescript/src/typescriptMain.ts
+++ b/extensions/typescript/src/typescriptMain.ts
@@ -16,6 +16,8 @@ import { env, languages, commands, workspace, window, Uri, ExtensionContext, Ind
 import * as nls from 'vscode-nls';
 nls.config({locale: env.language});
 
+import * as path from 'path';
+
 import * as Proto from './protocol';
 import TypeScriptServiceClient from './typescriptServiceClient';
 import { ITypescriptServiceClientHost } from './typescriptService';
@@ -39,6 +41,7 @@ interface LanguageDescription {
 	id: string;
 	diagnosticSource: string;
 	modeIds: string[];
+	extensions: string[];
 }
 
 export function activate(context: ExtensionContext): void {
@@ -51,12 +54,14 @@ export function activate(context: ExtensionContext): void {
 		{
 			id: 'typescript',
 			diagnosticSource: 'ts',
-			modeIds: [MODE_ID_TS, MODE_ID_TSX]
+			modeIds: [MODE_ID_TS, MODE_ID_TSX],
+			extensions: ['.ts', '.tsx']
 		},
 		{
 			id: 'javascript',
 			diagnosticSource: 'js',
-			modeIds: [MODE_ID_JS, MODE_ID_JSX]
+			modeIds: [MODE_ID_JS, MODE_ID_JSX],
+			extensions: ['.js', '.jsx']
 		}
 	]);
 
@@ -85,6 +90,7 @@ const validateSetting = 'validate.enable';
 class LanguageProvider {
 
 	private description: LanguageDescription;
+	private extensions: Map<boolean>;
 	private syntaxDiagnostics: Map<Diagnostic[]>;
 	private currentDiagnostics: DiagnosticCollection;
 	private bufferSyncSupport: BufferSyncSupport;
@@ -96,16 +102,19 @@ class LanguageProvider {
 
 	constructor(client: TypeScriptServiceClient, description: LanguageDescription) {
 		this.description = description;
+		this.extensions = Object.create(null);
+		description.extensions.forEach(extension => this.extensions[extension] = true);
 		this._validate = true;
 
 		this.bufferSyncSupport = new BufferSyncSupport(client, description.modeIds, {
 			delete: (file: string) => {
 				this.currentDiagnostics.delete(Uri.file(file));
 			}
-		});
+		}, this.extensions);
 		this.syntaxDiagnostics = Object.create(null);
 		this.currentDiagnostics = languages.createDiagnosticCollection(description.id);
 
+
 		workspace.onDidChangeConfiguration(this.configurationChanged, this);
 		this.configurationChanged();
 
@@ -220,7 +229,8 @@ class LanguageProvider {
 	}
 
 	public handles(file: string): boolean {
-		return this.bufferSyncSupport.handles(file);
+		let extension = path.extname(file);
+		return (extension && this.extensions[extension]) || this.bufferSyncSupport.handles(file);
 	}
 
 	public get id(): string {