diff --git a/src/vs/workbench/contrib/format/browser/formatActionsMultiple.ts b/src/vs/workbench/contrib/format/browser/formatActionsMultiple.ts
index a1799acde6326ee2f31558416b62cad596b54e92..390d3eb9be9a0f9749603f76573fe81ceb1720d4 100644
--- a/src/vs/workbench/contrib/format/browser/formatActionsMultiple.ts
+++ b/src/vs/workbench/contrib/format/browser/formatActionsMultiple.ts
@@ -128,7 +128,7 @@ class DefaultFormatter extends Disposable implements IWorkbenchContribution {
 			return <IIndexedPick>{
 				index,
 				label: formatter.displayName || formatter.extensionId || '?',
-				description: formatter.extensionId!.value
+				description: formatter.extensionId && formatter.extensionId.value
 			};
 		});
 		const langName = this._modeService.getLanguageName(document.getModeId()) || document.getModeId();