Story perspectives
Microsoft Investigates Outlook Crash Bug Affecting Users
10/3/2025
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Story summary
- Microsoft is investigating a bug in the classic Outlook for Windows client that crashes on startup.
- Users see an error message "Cannot start Microsoft Outlook," blocking mailbox access.
- The issue appears linked to mailbox throttling limits, impacting medium to large organizations with heavy authentication.
- Administrators are advised to capture network traffic with tools like Fiddler to diagnose the problem.
