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Here is the exact problem: you open an email in the new Outlook, click the small arrow on an attachment - and the menu has Preview, Save As and Download, but no "Open". Or you click the attachment, get an error that the file cannot be opened and that you should restart Outlook - and after the error, the Open option is gone completely. Your files are fine, your account is fine. Microsoft confirmed this on 28 October 2026 in advisory EX1528992, and the fix rollout began on 29 October. Work through the steps below in order.

New Outlook  ·  Attachment Menu
⚡Invoice-October.pdfOpen option missing

✔ Preview - available

✖ Open - missing from the menu completely

✔ Save As - available (this is the workaround)

✔ Download - available

✖ First clicks may show an error: the file cannot be opened, restart Outlook

✔ The same attachment opens normally in classic Outlook and on the web

The problem exactly as it appears: the attachment menu in the new Outlook loses its "Open" option after the Edge 156 update.

1

Confirm It Is This Exact Bug

This guide is for one specific failure, so check the match first:

  1. You are using the new Outlook for Windows (the app that looks like Outlook on the web) - not classic Outlook.
  2. The problem started around 28-29 October 2026, right after Microsoft Edge updated itself to version 156 in the background (the new Outlook displays mail using Edge WebView2 components, version 156.x - this is why a browser update could break a mail app).
  3. The attachment itself is healthy - it opens fine from Outlook on the web or after saving it.

Why it happens: in Microsoft's own words from advisory EX1528992, the Edge 156 update "unintentionally enabled an unnecessary configuration". Because the new Outlook is built on Edge components, that one configuration change disabled direct attachment opening for a portion of users. Nothing on your PC is corrupted - which is why repairing or reinstalling Outlook never fixed it for anyone.

2

Check Whether Microsoft's Fix Has Reached You ⭐

Microsoft started rolling out a fix on the morning of 29 October 2026 that disables the bad configuration again - from their side, so there is nothing to download. The rollout goes out in waves (Microsoft expected around 12 hours), and the change only takes effect when the app restarts. Do this now:

  1. Completely close the new Outlook - close the window, and make sure it is not still running in the system tray (bottom-right corner, near the clock). Right-click the tray icon and exit if you see it.
  2. Reopen the new Outlook and test an attachment. If Open is back in the menu, the fix has reached your account and you are done.
  3. If Open is still missing, open Microsoft Store → Library → Get updates and apply any waiting update for Outlook and for Microsoft Edge, then close and reopen Outlook once more.
  4. You can confirm your Edge version under Edge → Settings → About Microsoft Edge - version 156.x confirms you were in the affected wave.

If the menu is still missing its Open option after this, the rollout simply has not reached your account yet - go to Fix 3 and keep working; the option returns on its own once the fix lands, no action needed from you beyond one restart of the app.

3

The Save As Workaround (works right now)

While you wait for the fix, this is Microsoft's workaround - it adds one step per attachment, but every file opens normally:

  1. Open the email and click the small arrow on the attachment (or right-click the attachment).
  2. Choose Save As (in some builds the same action is labelled Download) and save the file to a folder you can find, for example Downloads or Desktop.
  3. Open the saved file from that folder with its normal program - double-click the PDF, Word file, image, and so on.

One housekeeping note: files you Save As stay on your PC until you delete them - they are copies, and editing one does not change the copy attached to the email. Clear out the folder once the direct Open option returns.

4

Still No Open Option After a Day? Run These Checks

If more than a day has passed since 29 October and attachments still will not open, work through these in order:

  1. Check Outlook on the web: open outlook.office.com (work/school account) or outlook.com (personal account), sign in and open the same attachment there. The web version is not affected by this bug, so work there for anything urgent.
  2. Repair the app: open Settings → Apps → Installed apps → Outlook (new) → Advanced options → Repair. Repair keeps your accounts and settings. Use Reset only as a last resort - you will sign in again afterwards.
  3. Use classic Outlook temporarily: if classic Outlook is installed on your PC, Microsoft has confirmed it is not affected by this problem - open attachments there until the new app is fixed.
  4. Ask your admin to check the advisory: on a work account, your IT admin can follow the live status under EX1528992 in the Microsoft 365 admin center → Service health. If the advisory still shows your tenant as impacted, the wait is on Microsoft's side, not your PC.
⚠️ Do not waste time on these: reinstalling Windows, creating a new mail profile, or "fixing" the attachment files themselves. The files were never broken, and restarting Outlook only helps after Microsoft's fix reaches your account - before that, the same error comes straight back. And if you use classic Outlook: you are not affected by this bug at all, so do not change anything.

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▶ Related video: confused between the new Outlook app in this guide and the classic one? Watch the full comparison: New Outlook App vs Classic Outlook - BIG Differences

Frequently Asked Questions

Why did attachments stop opening in the new Outlook?

An update to Microsoft Edge 156 unintentionally enabled an unnecessary configuration. The new Outlook renders mail using Edge (WebView2) components, so that configuration change broke direct attachment opening for some users - the Open option disappears, or an error says the file cannot be opened and tells you to restart Outlook. Microsoft confirmed the problem on 28 October 2026 in Exchange Online advisory EX1528992 and started rolling out a fix on 29 October that disables the configuration again.

What is advisory EX1528992?

EX1528992 is the ID of Microsoft's Exchange Online service health advisory for this incident. It covers the Edge 156 configuration problem that stopped some new Outlook users from opening attachments. Microsoft 365 admins can follow the fix status under this ID in the Microsoft 365 admin center, under Service health.

How long does the fix take to reach me, and what do I have to do?

Microsoft expected the configuration fix rollout to take around 12 hours from the morning of 29 October 2026, but it reaches accounts in waves, so your timing can differ. The fix is applied from Microsoft's side - there is nothing to download. Once it reaches your account, you must completely close the new Outlook and reopen it before the Open option comes back.

Is classic Outlook affected by the Edge 156 attachment problem?

No. According to Microsoft's EX1528992 advisory, classic Outlook does not appear to be affected. If you need to open attachments urgently and the fix has not reached you yet, you can temporarily work in classic Outlook, use Outlook on the web, or use the Save As workaround in the new Outlook.

Restarting Outlook did not help. Does that mean something else is broken?

Not necessarily. Restarting only helps after Microsoft's fix has reached your account - before that, the bad configuration is still active and the error comes straight back, which is exactly what affected users reported. Use Save As to save the attachment and open it from the folder until the fix lands, then close and reopen Outlook once.

Guide by Technical Anshu · Problem collected from real user reports; solution written and verified by Technical Anshu.