Is there a way to have guest account without # sign, in user id?

Question

During self-service signup the account gets created with a # sign, in their user IDs which cannot be synced to apps due to special character limitation, is there a way to remove the # sign automatically during signup?

Answer 1

Hi @RSahi ,

There isn't currently a way to remove the # sign. The “#” is a reserved character in UPNs for Microsoft Entra B2B collaboration or external users, because the invited account ******@contoso.com becomes user_contoso.com#EXT#@fabrikam.onmicrosoft.com. The guest user principal name contains the #EXT# identifier.

https://learn.microsoft.com/en-us/entra/external-id/troubleshoot#how-does--which-isnt-normally-a-valid-character-sync-with-azure-ad

https://learn.microsoft.com/en-us/entra/external-id/what-is-b2b

Note that UPN is not the value that links on-premises and cloud objects. That role is played by the sourceanchor (objectGUID by default). There are some workarounds mentioned in this thread that may suit your scenario, depending on where you are synchronizing the users. For example, you could use automatic user registration or import the members from a file.

As a sidenote, if you just need to query a B2B user using the userPrincipalName, you can encode the hash (#) character by replacing the # symbol with %23.

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