Microsoft is introducing a new file preview option in Microsoft Teams chat and channel conversations. This enhancement allows users to quickly review files without leaving the conversation, minimizing context switches and potentially enhancing efficiency.
Timeline
Rollout is expected between February and late March.
Update from 22 March 2025:
The rollout has been canceled and withdrawn. It will be continued at a later date.
Feature Details
The initial release will support previews for single file attachments in Teams messages, starting with PDF and PowerPoint files. Support for other popular formats such as Word, and later Excel will be added in subsequent updates. The preview option for messages containing multiple files will be supported in later releases.

With the file preview mode for PowerPoint files.
