diff --git a/src/vs/workbench/api/node/extHostOutputService.ts b/src/vs/workbench/api/node/extHostOutputService.ts
index 78a955a7330..8daae98da4e 100644
--- a/src/vs/workbench/api/node/extHostOutputService.ts
+++ b/src/vs/workbench/api/node/extHostOutputService.ts
@@ -32,6 +32,7 @@ class OutputAppender {
 
 	append(content: string): void {
 		this.appender.critical(content);
+		this.flush();
 	}
 
 	flush(): void {