USERPRINCIPALNAME is blank for External Customer

- Blank USERPRINCIPALNAME() usually means the user isn’t properly authenticated.
- Make sure they’re accessing the report via Power BI Service, not an embedded or anonymous link.
- Confirm they’ve been added as a Guest user in Azure AD and accepted the invite.
- Try disabling RLS temporarily to see if it’s filtering them out.
- Use a raw measure like ShowUPN = USERPRINCIPALNAME() with no conditions.

Hello,

To narrow this down, please check the following:

• How is the card built, does it display a column or a measure? What fields are inside the visual?

• Are there any additional filters on the visual?

• Could RLS be affecting this visual for your role?

If you haven’t already, create a new blank page and add only a card with the measure USERPRINCIPALENAME to verify which identity the model sees.

Hi c_lovestrom ,
Thank you for providing the details. This behavior is expected in certain scenarios with B2B guest users, as the USERPRINCIPALNAME() function may return a blank value when a UPN claim is not provided by some external identities.

You may consider the following alternatives:

Utilize USEROBJECTID() for RLS mapping, which offers greater reliability for both internal and external users.

Alternatively, implement a fallback expression such as:

Identifier =
IF(
    ISBLANK(USERPRINCIPALNAME()),
    USERNAME(),
    USERPRINCIPALNAME()
)

This approach ensures that if the UPN is unavailable, the system will default to the username or email. Additionally, please confirm that the external guest has fully accepted the Azure AD invitation and is signing in with their work account, as an incomplete setup may also result in a blank UPN.