Team channel messages
Everyone in a Team, including guests, can share files in the Teams channel conversation. These files are stored in your Team's SharePoint environment and are shared with every team member.
In a person-to-person chat, a guest user cannot share files.
Microsoft Teams uses a personal OneDrive folder (called Microsoft Teams Chat Files) to share files in a person-to-person chat. The files uploaded in the chat will be placed in that folder and are automatically shared with the person you’re chatting with. As a guest user, you don't have a personal OneDrive. This prevents you from sharing files. However, it is possible to share files from an internal account to a guest.
Alternatives for sharing files with a guest
If you’re chatting with a guest who is not a member of a Team that you’re part of, the fastest way to share files is through e-mail.
When a guest is a member of your team and only wants to share files with you, you can create a new private channel in your Team and add the guest as a member. Now you can share files in the tab Posts.
- Click on the 3-dots behind your Team
- Select Add channel
- Give your channel a name and select Private