SharePoint folder sharing to external users inconsistent (no external users are created)

Question

Hello

Issue:

a) We'd like to share a SharePoint Folder from MS365 Tenant A to a user in MS365 Tenant B. (= to an external user)

b) The user in Tenant B should be able to sync that folder to his PC using the OneDrive client which - as far as I know - requires that the sharing happens in a way where an external user is created in Tenant A

c) However, when we share from Tenant A, there is never an external user created. Instead the user from tenant B gets an invite email (as it should be) but then is required to authenticate with an one-time-code sent to their email. So user B can view the folder in the web but not sync it to their OneDrive.

What we already found out:

Whether an external user is created in a tenant or the sharing happens without an external user being created seems to depend on some settings (on Tenant A, most likely) - but we haven't found out yet which settings that are. (Of course "share to new and existing guests" is allowed in the SharePoint settings.)

In fact we have tested it with two additional Tenants (C and D) and have indeed observed different behaviour:

Tenant C behaves like Tenant A: when sharing a folder from SharePoint, no external user is created and the "receiving" user can't sync

Tenant D behaves like we want it: when sharing a folder from SharePoint, an external user is created and the "receiving" user can sync

Question: which setting(s) do we have to change in Tenant A/C so that they behave like Tenant D?

Thank you!

Answer 1

Hi @david-cslu,

As said in this article: Overview of external sharing in SharePoint and OneDrive in Microsoft 365, there are two external sharing models used in SharePoint and OneDrive:

• SharePoint external authentication
• SharePoint and OneDrive integration with Microsoft Entra B2B

Your tenant will automatically create a guest user after enabling SharePoint and OneDrive integration with Microsoft Entra B2B. To enable SharePoint and OneDrive integration with Microsoft Entra B2B, you can use the following cmdlets:

Set-SPOTenant -EnableAzureADB2BIntegration $true

Once the integration is enabled you and your users don't have to reshare or do any manual migration for guests previously shared with. Instead, when someone outside your organization clicks on a link that was created before Microsoft Entra B2B integration was enabled, SharePoint automatically creates a B2B guest account. This guest account is created for the user who originally created the sharing link. (If the user who created the link is no longer in the organization or no longer has permission to share, the guest won't be added to the directory and the file will need to be reshared.)

---

If the answer is helpful, please click "Accept as Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.