I have attempted to change the Display Name Format in the User Settings for DNN 7 with the following token:
[FIRSTNAME]
But for some reason DNN isn't displaying it like that anywhere across the site. It's still displaying it like [LASTNAME], [FIRSTNAME].
How do I fix this without manually having to go through thousands of automatically populated records?
For your existing users you will likely need to update it manually in the Database.
Not positive, but I believe DisplayName is on the User's Table, so you could update it there for each user using a t-sql statement.