Cross tenant OneDrive access

[YashikaAgrawal]

Hi Team,

We are using Microsoft Entra External ID for business-to-business (B2B) collaboration and granting member-level access to OneDrive and SharePoint.

We are working on a Power BI migration from tenant INFY to tenant TATA.
Only users, SharePoint, and OneDrive are migrating to the TATA tenant (i.e., for TATA users).

Current system: INFY tenant has both INFY users and TATA users.
Example: pete@INFY.com and brett@TATA.com both access Power BI and Pete’s personal OneDrive, e.g., c:\users\INFY\onedrive_group\d_prefix.csv.

Now, Brett@TATA.com has been migrated fully to the TATA tenant.

Question:
Can Brett, using Azure AD B2B member access, still access Pete’s personal OneDrive which is located in the INFY tenant if given permission?

Thanks,

[rohit1991 · Accepted solution]

Hi @YashikaAgrawal 

Yes, Brett can still access Pete’s OneDrive in the INFY tenant, but only if Pete explicitly shares the files or folders with Brett’s new TATA account and Brett is recognized as a guest user in INFY through Azure AD B2B. OneDrive is always tied to the user’s home tenant, so Pete’s storage will remain in INFY even after the migration, and Brett’s old INFY identity will no longer work once he has fully moved to TATA. For Brett to continue access, Pete needs to re-share the content with brett@TATA.com, and Brett must sign in using his TATA identity under the guest context of the INFY tenant. Once that is done, Brett can securely open and use Pete’s files across tenants, but only with the rights Pete grants. This setup ensures that sharing is still controlled by the INFY tenant while enabling seamless access for Brett after the migration.