Microsoft Outlook for Windows will allow users to add file attachments to emails while offline, sending them automatically when reconnected. Rollout starts mid-August 2025 for Targeted Release and mid-October 2025 for General Availability. Admins can manage this via the OWAMailboxPolicy-OfflineEnabledWin policy.
Introduction
We’re enhancing offline functionality in the new Microsoft Outlook for Windows. This update (Microsoft 365 Roadmap ID 496371) enables users to add file attachments while composing emails offline, improving productivity for those working without an internet connection.
When this will happen
How this affects your organization
Users with offline mode enabled in the new Outlook for Windows will be able to attach files to draft emails while offline. These emails, including attachments, will be sent automatically once the device reconnects to the internet.
This feature will be on or off by default based on your current configuration of the OWAMailboxPolicy-OfflineEnabledWin
policy. No changes will be made to existing configurations.
What you can do to prepare
To enable this functionality, ensure the following settings are configured in the new Outlook under Settings > General > Offline:
Admins can manage this feature using the OWAMailboxPolicy-OfflineEnabledWin
mailbox policy. Learn more at Set-OwaMailboxPolicy.
Caption i. Offline editing can be enabled or disabled in Settings > General > Offline
Compliance considerations
No compliance considerations identified, review as appropriate for your organization.