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Windows Mail App Won't Open or Keeps Crashing

Applies to: the built-in Mail app on Windows 11 and Windows 10

MSWritten by Maria Santos, Email Systems Writer · Last reviewed Aug 2026
Quick answer: Close it via Task Manager and reopen, check for pending Windows and Mail app updates, then use Repair (not Reset) under the app's Advanced options first — but if the app won't send or receive at all rather than just crashing, see the notice below first.
Important context: Microsoft ended support for the classic Windows Mail and Calendar app on December 31, 2024. Even if the app opens and looks normal, it can no longer send or receive new email past that date. If it's genuinely refusing to launch or crashing, the steps below can still help — but if it opens fine and just sits there with no new mail arriving, that's the retirement, not a bug, and the fix is switching to the new Outlook for Windows app instead.

App opens fine but just isn't syncing? That's our Windows Mail not syncing guide instead. This one's about the app refusing to launch at all, or crashing once it does.

1. Restart the app cleanly

  1. If it's unresponsive, close it entirely via Task Manager — right-click the taskbar → Task Manager → find Mail and Calendar → End Task.
  2. Reopen it and give it a moment before deciding it's frozen — the first launch after a Windows update can genuinely take longer than usual.

2. Check for pending Windows updates

The Mail app is tied closely to the OS, and a pending update can cause exactly this kind of instability. Settings → Windows Update → install anything pending, then restart.

3. Update the app itself

  1. Microsoft Store → Library → check for updates to Mail and Calendar specifically.
  2. Install anything available, even if Windows itself is fully current — app and OS updates run on separate tracks.

4. Repair the app

  1. Windows Settings → Apps → Installed apps → find Mail and Calendar → Advanced options.
  2. Click Repair first. It fixes a lot of crash issues without touching your accounts or settings.

5. Reset the app (last resort)

Repair didn't help? Use Reset in the same Advanced options screen. It clears the app's local data and accounts entirely — you'll re-add everything after, but nothing gets deleted from the actual mail servers.

If it crashes specifically when opening one account's folder or message, try removing just that account first before resetting the whole app. The problem might be isolated to one corrupted local sync database, not the app itself.

FAQ

Should I try Repair or Reset first?

Repair, not Reset — Repair fixes issues without deleting your app data and settings, while Reset clears everything and starts fresh. Reset should be a last resort, not a first attempt.

Will closing it via Task Manager lose any unsaved work?

It can, if you have an unsent draft open — check for anything unsaved before force-closing if possible, though this is rarely an issue for a crashing app you're troubleshooting anyway.

What if the app won't send or receive at all, rather than crashing?

That's a different, more serious situation — the classic Windows Mail app was officially retired at the end of 2024 and can no longer send or receive mail regardless of troubleshooting. See the notice at the top of this guide before working through the crash-specific steps.

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