How to share Teams channel files with externals

Question

We need to share files posted in a Teams channel with external guest users. When we create a Teams channel with an external org, messages are OK, but neither side can see any files posted by the other in the files tab. I am aware that the files can be shared individually with externals via Sharepoint, but the external tenant in question is owned by us. What we want to do is enable some kind of organisational trust so the files tab in a Team will show the files and they be accessible from either org seamlessly, without having to switch accounts in Teams. The documentation of a m365 group suggests that this content should be shared by all the members of the group but it doesn't seem to be the case.
This external tenant is eventually going to have all the users and mailboxes and other content migrated to the parent company and will eventually be collapsed, so we aren't looking to setup as multi-tenant org at this time. This Teams/Sharepoint trust will only required until the migration occurs.

So, looking for options how we can achieve this.

Answer 1

Hi @Bob Pants
According to your case description, you want to achieve seamless file sharing with external organizations in Microsoft Teams. As you said, you can collaborate with people outside the organization through shared links of documents in SharePoint or OneDrive.

In addition, you can enable organizational trust to achieve collaboration through shared channels. According to our official documentation, external sharing of shared channels is enabled by default in Teams, but the Microsoft Entra cross-tenant access settings for B2B Direct Connect must also be configured to share channels externally. By default, these settings are set to block all organizations.

Enable shared channels in Teams

Shared channels is enabled by default in Teams. Follow this procedure to confirm the settings.

To configure shared channels

1. In the Teams admin center, expand Teams, and then select Teams policies.
2. Select the policy for which you want to enable shared channels, and then select Edit.
3. Select the options you want to enable:
   • To allow team owners to create shared channels, turn Create shared channels on.
   • To allow team owners to share shared channels with people outside the organization, turn Invite external users to shared channels on.
   • To allow users to be invited to shared channels in other organizations, turn Join external shared channels on.
4. Select Apply.

In order for external channel participants to participate in meetings, external access must be enabled. This is also required to be able to see external participants' presence in the channel.

Enable external access

To enable external access

1. In the Teams admin center, expand Users, and then select External access.
2. Under Teams and Skype for Business users in external organizations, ensure that the organizations that you want to collaborate with are not blocked.

Configure cross-tenant access settings in Microsoft Entra External ID

Microsoft Entra External ID B2B direct connect is disabled by default. To enable collaboration in shared channels with people from other organizations, you must:

1. Add an organization.
2. Configure inbound settings for the organization to allow users from the organization to be invited to your shared channels.
3. Configure outbound settings for the organization to allow your users to be invited to the other organization's shared channels.

Note: Changes to cross-tenant access settings may take up to six hours to take effect.

For more detailed instructions, please refer to Collaborate with external participants in a shared channel and Enable shared channels with all external organizations.

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