diff --git a/src/vs/workbench/parts/debug/electron-browser/repl.ts b/src/vs/workbench/parts/debug/electron-browser/repl.ts
index 6fe45c3e0ed550f5a07b6fafc1cb30d451df06d6..19e1cd65cd4b36132bfaaab41b4de77d59345eb7 100644
--- a/src/vs/workbench/parts/debug/electron-browser/repl.ts
+++ b/src/vs/workbench/parts/debug/electron-browser/repl.ts
@@ -183,7 +183,9 @@ export class Repl extends Panel implements IPrivateReplService, IHistoryNavigati
 
 	clearRepl(): void {
 		const session: IDebugSession = this.tree.getInput();
-		session.removeReplExpressions();
+		if (session) {
+			session.removeReplExpressions();
+		}
 		this.replInput.focus();
 	}