Microsoft needs to stop forcing New Outlook as default!!!!! Until features match classic Outlook

Dear @Zoe,

Good day! Welcome to Microsoft Q&A forum!

Based on your description, it appears that the New Outlook for Windows is being reinstalled and set as the default following Windows updates. You are seeking a way to prevent New Outlook from being automatically enabled or set as the default until the necessary legacy Outlook features are available.

Regarding this situation, to help prevent New Outlook from being installed or set as the default on your PCs, Microsoft provides supported configuration options that allow organizations to control this behavior. I recommend reviewing and following the step‑by‑step instructions in the article below, which explains how to block or manage the New Outlook installation and keep Classic Outlook as the default: Control installing and using new Outlook

This guide includes:

• How to prevent New Outlook from being installed or automatically enabled
• Registry and policy-based options for IT-managed environments
• Ways to ensure Classic Outlook remains available and default

If your IT department hasn’t already implemented these specific controls, this documented approach should provide a more stable and long‑term solution.

Thank you for your feedback and understanding!

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To prevent being forced into new Outlook and keep using classic Outlook with MYOB integration, configure Windows and Outlook to hide and block the new experience.

1. Ensure classic Outlook is installed and configured on each PC.
2. Hide the “Try the new Outlook” toggle so Microsoft cannot auto-enable it:
   • Set this registry value:
     • Key: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General
     • DWORD: HideNewOutlookToggle
     • Value: 1
   • Deploy this via script or Group Policy so it is re-applied for all users.
3. Keep classic Outlook as the default mail client so MAPI integrations (like MYOB) always target classic Outlook. New Outlook is not MAPI-compliant and cannot replace classic Outlook for these scenarios yet.
4. For environments deploying new Outlook, follow Microsoft guidance to run classic Outlook and new Outlook side‑by‑side so MAPI-based workflows (MYOB, “Send to → Mail recipient”, “Share link in Outlook”, mail merge, etc.) continue to use classic Outlook.

This approach stops the new Outlook switch UI, keeps classic Outlook as the MAPI mail client, and avoids the repeated prompts and delays when sending large volumes of remittances and payslips.

References:

• New Outlook users unexpectedly see the “Welcome to Outlook 2016" setup wizard
• Deployment overview for the new Outlook for Windows
• Overview of the new Outlook for Windows
• Manage updates in new Outlook for Windows
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