diff --git a/src/vs/workbench/api/node/extHostExtensionService.ts b/src/vs/workbench/api/node/extHostExtensionService.ts
index 643f65a6aaf2ed741c8b7ccd5e36889b53947cce..c536032243154d8425c3370799ae9e4c1590882d 100644
--- a/src/vs/workbench/api/node/extHostExtensionService.ts
+++ b/src/vs/workbench/api/node/extHostExtensionService.ts
@@ -562,8 +562,8 @@ export class ExtHostExtensionService implements ExtHostExtensionServiceShape {
 							c();
 							this._gracefulExit(0);
 						})
-						.catch((err) => {
-							e(err);
+						.catch((err: Error) => {
+							e(err.toString());
 							this._gracefulExit(1);
 						});
 				}