Outlook for iOS may become unresponsive or crash on launch

Last Updated: September 18, 2026

ISSUE

Customers using Outlook for iOS version 5.2635.1 on older versions of iOS may experience an issue where Outlook becomes unresponsive during startup or crashes when launched.

STATUS: INVESTIGATING

Microsoft Engineering is reviewing the issue to determine whether client-side changes can be made to address the behavior.

WORKAROUND

To work around this issue, update the device to the latest available version of iOS.

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See Also

Fixes or workarounds for Outlook mobile apps