This happens, it can be fixed simply. In the webui where you create the address book, look to the dropdown on the far right.
Use it to Export the address book and save it to your desktop (Don’t check the “Legacy mode” option)
Then use it to Delete All
Then use it to Import from file from your desktop (Choose option 2 if prompted)
It will now allow you to populate the new user(s)
There is a bug that causes the issue, it has affected every firmware level and this is the only known workaround, luckily it works in every case and is simple to do. The machine doe snot need to be reloaded or rebooted, just 3 steps that take under 2 minutes.
Thank you for using the Support Forum. Please take a look at the solution for the "display name already exists" message. If this solution does not help please consider contacting your support centre for further assistance.
Trying to add an entry into the address book on a Xerox Workcentre 5855. When I click save, no matter what I have in the display name field, I get an error that says "display name already exists". I've even tried completely random words and phrases just to give it a shot. I have seen other postings about this problem, but I have not seen a solution. Anyone know of one?