diff --git a/src/vs/workbench/contrib/debug/browser/debugSession.ts b/src/vs/workbench/contrib/debug/browser/debugSession.ts
index 7aa4b67fd25eeac4d3575d5b161e1eb4ebd21483..a6c75b4d2aed35937ad80634ee6a9c30cd42f222 100644
--- a/src/vs/workbench/contrib/debug/browser/debugSession.ts
+++ b/src/vs/workbench/contrib/debug/browser/debugSession.ts
@@ -904,6 +904,7 @@ export class DebugSession implements IDebugSession {
 			this.raw.dispose();
 		}
 		this.raw = undefined;
+		this.fetchThreadsScheduler = undefined;
 		this.model.clearThreads(this.getId(), true);
 		this._onDidChangeState.fire();
 	}