diff --git a/src/vs/workbench/api/browser/mainThreadProgress.ts b/src/vs/workbench/api/browser/mainThreadProgress.ts
index f038168e205..f64fd22a202 100644
--- a/src/vs/workbench/api/browser/mainThreadProgress.ts
+++ b/src/vs/workbench/api/browser/mainThreadProgress.ts
@@ -40,7 +40,7 @@ export class MainThreadProgress implements MainThreadProgressShape {
 		this._progress.clear();
 	}
 
-	$startProgress(handle: number, options: IProgressOptions, extension?: IExtensionDescription): void {
+	async $startProgress(handle: number, options: IProgressOptions, extension?: IExtensionDescription): Promise<void> {
 		const task = this._createTask(handle);
 
 		if (options.location === ProgressLocation.Notification && extension && !extension.isUnderDevelopment) {
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index 95be5a6d27a..5ca2c6ab247 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -453,7 +453,7 @@ export interface MainThreadOutputServiceShape extends IDisposable {
 
 export interface MainThreadProgressShape extends IDisposable {
 
-	$startProgress(handle: number, options: IProgressOptions, extension?: IExtensionDescription): void;
+	$startProgress(handle: number, options: IProgressOptions, extension?: IExtensionDescription): Promise<void>;
 	$progressReport(handle: number, message: IProgressStep): void;
 	$progressEnd(handle: number): void;
 }
diff --git a/src/vs/workbench/api/common/extHostProgress.ts b/src/vs/workbench/api/common/extHostProgress.ts
index 100cbd8a906..f25fb54faa6 100644
--- a/src/vs/workbench/api/common/extHostProgress.ts
+++ b/src/vs/workbench/api/common/extHostProgress.ts
@@ -22,12 +22,12 @@ export class ExtHostProgress implements ExtHostProgressShape {
 		this._proxy = proxy;
 	}
 
-	withProgress<R>(extension: IExtensionDescription, options: ProgressOptions, task: (progress: Progress<IProgressStep>, token: CancellationToken) => Thenable<R>): Thenable<R> {
+	async withProgress<R>(extension: IExtensionDescription, options: ProgressOptions, task: (progress: Progress<IProgressStep>, token: CancellationToken) => Thenable<R>): Promise<R> {
 		const handle = this._handles++;
 		const { title, location, cancellable } = options;
 		const source = { label: localize('extensionSource', "{0} (Extension)", extension.displayName || extension.name), id: extension.identifier.value };
 
-		this._proxy.$startProgress(handle, { location: ProgressLocation.from(location), title, source, cancellable }, extension);
+		await this._proxy.$startProgress(handle, { location: ProgressLocation.from(location), title, source, cancellable }, extension);
 		return this._withProgress(handle, task, !!cancellable);
 	}