diff --git a/src/main/updater.startup-scheduling.test.ts b/src/main/updater.startup-scheduling.test.ts
index 06a1ea041be..a58fa0af049 100644
--- a/src/main/updater.startup-scheduling.test.ts
+++ b/src/main/updater.startup-scheduling.test.ts
@@ -27,7 +27,12 @@ vi.mock('./local-builds/local-build-feed-server', () => moduleFactories.localBui
 
 describe('updater', () => {
   beforeEach(() => {
+    // Why: resetUpdaterMocks() uninstalls fake timers, which discards every timer the previous test
+    // armed; re-faking here keeps this test's timers discardable too. On real timers a stale
+    // `vi.resetModules()`-orphaned updater instance survived to re-arm its 24h check inside a later
+    // fake-timer test, adding a phantom checkForUpdates at fake offset 24h.
     resetUpdaterMocks()
+    vi.useFakeTimers()
   })
 
   it('does not load or configure electron-updater during dev setup', async () => {