On October 29, 2026, a software update caused certain users of the New Outlook for Windows to lose the ability to open email attachments. This disruption is linked to an update for the Microsoft Edge WebView2 Runtime 156.x component. According to reporting by The Register, Microsoft initiated a rollout for a targeted settings fix to resolve the error.
Understanding the WebView2 156 Update Failure
The core problem stems from an unintended setting activated within Edge WebView2 156.x builds. When users attempt to interact with files inside their emails, the standard Open command may vanish entirely from the interface. Alternatively, the application may display an error message stating that it cannot open the file and prompting a restart.
User reports within the Microsoft WebView2 issue tracker specifically implicate runtime versions 156.0.4314.42 and 156.0.4314.50. Comparative user observations indicate that the preceding 155.0.4283.62 release did not exhibit this behavior. However, system behavior varies across different machines even when running closely aligned software builds, and Classic Outlook appears entirely unaffected by the glitch.
Microsoft Fix Rollout and Technical Details
Microsoft issued service advisory EX1528992 on October 28 to document the disruption. Engineer Ojasvi Das noted in the WebView2 issue tracker on October 29 that the development team identified the root cause and initiated a deployment of the stable-channel fix. This remediation utilizes a remote kill switch on the runtime rather than a traditional binary update delivered through the standard Edge Updater mechanism.
Initial estimates projected a 12-hour window for the settings fix rollout, though this timeframe serves as an approximation rather than a guarantee of immediate delivery to every affected computer. Administrators can monitor Microsoft 365 Service health for advisory EX1528992 to track progress. Users can check whether the fix has reached their system by closing and reopening New Outlook, though a simple restart does not confirm that the backend deployment has arrived on that specific device.
Workarounds and Safety Precautions
While the global deployment progresses, users have several viable pathways to access necessary files without modifying core system components. Uninstalling Edge or manually downgrading WebView2 is strongly discouraged due to potential system instability. The table below outlines the supported options and their respective trade-offs based on current evidence.
| Option | What the evidence supports | Trade-off |
|---|---|---|
| Save As, then File Explorer | The Register reports this as a workaround while Microsoft’s settings fix rolls out. | Adds a save step while opening it in the app is broken. |
| Classic Outlook | The Register says it did not appear to have the same issue. | Requires another Outlook app where available. |
| Outlook on the web | A Microsoft Q&A discussion describes desktop-opening failures; user reports in the WebView2 issue tracker say downloading or opening in a browser worked for them. | May offer another access route; not confirmed for every affected attachment and does not repair New Outlook. |
| Wait for Microsoft’s settings fix | The Register says the rollout began October 29. You’ll need to restart New Outlook after the fix arrives. | The reported 12-hour estimate is not a guarantee for each PC; completion remains unconfirmed. |
Security vigilance remains essential during this period. Saving an attachment does not inherently verify its safety, and users should always confirm unexpected messages directly with the sender before interacting with downloaded documents. Additionally, running downloaded files through local security software provides an extra layer of protection while waiting for the Outlook attachment issue to resolve completely.
