New Outlook disappeared

It sounds like you're experiencing a frustrating issue with the installation of the New Outlook on your Windows machine. Here are some steps you can take to troubleshoot the problem:

1. Check Firewall and Proxy Settings: Ensure that your firewall or proxy settings are not blocking access to the Microsoft Store, which is necessary for downloading and installing the New Outlook. The URLs that should be accessible are:
   • https://res.cdn.office.net
   • https://res.cdn.office.net/nativehost/5mttl/installer/
2. Verify Executable Permissions: Make sure there are no security policies or software (like AppLocker, Anti-Virus, or Group Policy) that are blocking executables from running in your temp directory. The installer file you need to execute is NewOutlookInstaller.exe.
3. Check Download Mode: The download mode setting can affect installation. For Windows 11, ensure that the DODownloadMode value in the registry is set to 0. For Windows 10, the same applies. You can find this setting under:
   • HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\DeliveryOptimization
4. Remove Old Versions: Before reinstalling, ensure that any remnants of the Classic Outlook are completely removed. You can use the PowerShell command to remove the new Outlook for all users:

      Remove-AppxPackage -AllUsers -Package (Get-AppxPackage Microsoft.OutlookForWindows).PackageFullName
   

5. Reboot and Retry: After making these changes, reboot your machine and try installing the New Outlook again.

If the issue persists, consider reaching out to Microsoft Support for further assistance, especially since you mentioned that your organization relies on the New Outlook for specific applications.

References:

• Resolve installation issues in the new Outlook for Windows
• Control the installation and use of new Outlook

Hi @Ed ant, 

Welcome to the Microsoft Q&A forum.  

Thank you for letting us know about the situation. Based on your description, New Outlook disappeared after the 25H2 upgrade and the toggle appears to download but never launches. We recognize how important New Outlook is for your setup and appreciate the time you’ve already invested in troubleshooting. 

New Outlook relies on modern app components and local data folders. After certain Windows updates or incomplete app processes, background Outlook tasks can linger, app cache can become inconsistent, or local authentication folders can block a clean start. Addressing these items directly helps the app start normally.  

Below are some workarounds that suit for your situation: 

Option 1: Begin by repairing or reinstalling Microsoft Edge WebView2, as it is required for New Outlook.

New Outlook won’t launch if the WebView2 runtime is missing or corrupted. 

• Download Microsoft Edge WebView2 – Evergreen Standalone Installer (official Microsoft page). 
• Right‑click → Run as administrator, complete the install/repair. 
• Restart Windows, then open Outlook (new) from Start. 

Option 2: Proceed with installation using the offline bootstrapper to avoid the toggle and Store limitations. 

This forces the Microsoft.OutlookForWindows package to be provisioned to the device and starts the app, even when the toggle “downloads but does nothing”. 

• Download Microsoft’s Setup.exe for New Outlook (official CDN). 
• Open Windows Terminal / PowerShell (Admin) in the folder where you saved it. 
• Run: .\Setup.exe --provision true --quiet --start- 
• After it finishes, search Start for Outlook (new) and open it. 
  • If provisioning succeeds but you still don’t see the app, verify the package exists:

 (get-appxpackage Microsoft.OutlookForWindows).InstallLocation   

Option 3: After that, eliminate network-level blocks to enable MSIX app installation and update processes. 

Device policies or firewall settings can silently prevent New Outlook from installing or launching. 

• Group Policy (gpedit.msc) → Computer Configuration → Administrative Templates → Windows Components → App Package Deployment 
  • Prevent non‑admin users from installing packaged Windows apps = Not configured 
  • Allow all trusted apps to install = Not configured 
• Firewall/Proxy: ensure Microsoft endpoints are allowed (e.g., res.cdn.office.net, Office/Microsoft Store CDNs). 
• If Store is allowed, also repair Store components: 
  • Press Win + R, run wsreset.exe 
  • Settings > Apps > System components → App Installer and Microsoft Store → Advanced options > Repair (then Reset if needed) 

For your information that you can concern: 

• Resolve Installation Issues in the New Outlook for Windows - Outlook | Microsoft Learn 
• How to Fix New Outlook App Not Opening or Working 
• New Outlook app not working or opening 

Note: Microsoft provides this information only as a convenience to users. These websites are not controlled by Microsoft, and Microsoft does not guarantee the quality, security, or suitability of any software or information on them. It is important to fully understand the risks involved before using any of the suggestions in the links above.  

If the app still doesn’t open after these steps, please share what you see (for example, any message or specific behavior), and we’ll guide you through the next action. 

As community moderators, we appreciate your understanding that our access to internal development details is limited. Our primary role is to guide users toward the appropriate resources and support channels. While we may not have visibility into deeper backend analysis, we’ll continue doing our best to support you within the scope of our responsibilities.  

I hope this information is helpful. Please follow these steps and let me know if it works for you. If you have any updates regarding the issue, please feel free to share them with me.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.   

I look forward to continuing the conversation.

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