Certain users enrolled in the Microsoft 365 Insiders Program cannot launch classic Outlook for Windows

Last Updated: July 21, 2025

ISSUE

Certain users enrolled in the Microsoft 365 Insiders program who are running versions 16.0.19113.20000 or 16.0.19115.20000 may experience crashes when attempting to launch classic Outlook for Windows. 

STATUS: FIXED

This issue has been fixed in build 16.0.19119.20000. To resolve this issue, affected users should launch an Office app and update their Office version to build 16.0.19119.20000 or greater. For more details, please go to How to update Microsoft 365 or Office for Windows.

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Fixes or workarounds for recent issues in classic Outlook for Windows