UPN sync changes $ to _

Occasional Contributor

So, I have a weird situation.  I have a customer that starts all their admin accounts with $ in the username and UPN.  We've noticed that when we sync these accounts to O365, the $ is changed to _, which is odd because most of the time when there's an invalid character in the UPN you get an error in Synchronization Service.


My question is - Is this expected behavior, changing the $ to _?  Personally, my recommendation is to remove the $ from the UPN and keep it for the domain\username, but considering the customer I would like to have more information first.

1 Reply

@Raechel Moermond 


This is by design, see article




Even through dollar ($) is not explicitly on this list the list itself is not exhaustive and can be expected to extend to other special characters such as Pound (£) Hash (#) and Brackets ([]). I myself have experienced this with Dollar, Hash and Ampersand.


I would recommend what you said - remove these types of special characters completely and change them to something supported like ADM_username


Hope that answers your question


Best, Chris