diff --git a/src/tsconfig.strictNullChecks.json b/src/tsconfig.strictNullChecks.json
index d2622ab91ea..fb3756323ab 100644
--- a/src/tsconfig.strictNullChecks.json
+++ b/src/tsconfig.strictNullChecks.json
@@ -775,6 +775,7 @@
 		"./vs/workbench/test/common/editor/editorOptions.test.ts",
 		"./vs/workbench/test/common/notifications.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHost.api.impl.test.ts",
+		"vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostDocumentData.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostMessagerService.test.ts",
 		"./vs/workbench/test/electron-browser/api/extHostTypes.test.ts",
diff --git a/src/vs/workbench/api/node/extHostWorkspace.ts b/src/vs/workbench/api/node/extHostWorkspace.ts
index a0fec19ef9c..4cd66f5e7c6 100644
--- a/src/vs/workbench/api/node/extHostWorkspace.ts
+++ b/src/vs/workbench/api/node/extHostWorkspace.ts
@@ -56,7 +56,7 @@ interface MutableWorkspaceFolder extends vscode.WorkspaceFolder {
 
 class ExtHostWorkspaceImpl extends Workspace {
 
-	static toExtHostWorkspace(data: IWorkspaceData, previousConfirmedWorkspace?: ExtHostWorkspaceImpl, previousUnconfirmedWorkspace?: ExtHostWorkspaceImpl): { workspace: ExtHostWorkspaceImpl | null, added: vscode.WorkspaceFolder[], removed: vscode.WorkspaceFolder[] } {
+	static toExtHostWorkspace(data: IWorkspaceData | null, previousConfirmedWorkspace?: ExtHostWorkspaceImpl, previousUnconfirmedWorkspace?: ExtHostWorkspaceImpl): { workspace: ExtHostWorkspaceImpl | null, added: vscode.WorkspaceFolder[], removed: vscode.WorkspaceFolder[] } {
 		if (!data) {
 			return { workspace: null, added: [], removed: [] };
 		}
@@ -198,7 +198,7 @@ export class ExtHostWorkspaceProvider {
 
 	constructor(
 		mainContext: IMainContext,
-		data: IWorkspaceData,
+		data: IWorkspaceData | null,
 		private _logService: ILogService,
 		private _requestIdProvider: Counter
 	) {
diff --git a/src/vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts b/src/vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts
index 25213f7c845..e8d1abc034c 100644
--- a/src/vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts
+++ b/src/vs/workbench/test/electron-browser/api/extHostConfiguration.test.ts
@@ -56,7 +56,7 @@ suite('ExtHostConfiguration', function () {
 
 		assert.equal(extHostConfig.getConfiguration('search.exclude')['**/node_modules'], true);
 		assert.equal(extHostConfig.getConfiguration('search.exclude').get('**/node_modules'), true);
-		assert.equal(extHostConfig.getConfiguration('search').get('exclude')['**/node_modules'], true);
+		assert.equal(extHostConfig.getConfiguration('search').get('exclude')!['**/node_modules'], true);
 
 		assert.equal(extHostConfig.getConfiguration('search.exclude').has('**/node_modules'), true);
 		assert.equal(extHostConfig.getConfiguration('search').has('exclude.**/node_modules'), true);
@@ -167,7 +167,7 @@ suite('ExtHostConfiguration', function () {
 		});
 
 		const testObject = all.getConfiguration();
-		let actual = testObject.get('farboo');
+		let actual: any = testObject.get('farboo');
 		assert.deepEqual(JSON.stringify({
 			'config0': true,
 			'nested': {
@@ -190,7 +190,7 @@ suite('ExtHostConfiguration', function () {
 			'config4': ''
 		}), JSON.stringify(actual));
 
-		actual = testObject.get('workbench')['colorCustomizations']!;
+		actual = testObject.get('workbench')!['colorCustomizations']!;
 		actual['statusBar.background'] = 'anothervalue';
 		assert.deepEqual(JSON.stringify({
 			'statusBar.foreground': 'somevalue',
@@ -241,7 +241,7 @@ suite('ExtHostConfiguration', function () {
 			}
 		});
 
-		let testObject = all.getConfiguration();
+		let testObject: any = all.getConfiguration();
 
 		try {
 			testObject['get'] = null;