I have a few users who are without emails.
I forgot to turn off the user template for emails.
when I edit them and turn off zarafa and press change.
{"msg":"Zarafa account options set","meeting_autoaccept":0,"success":1,"userDN":"uid=user13,ou=DropIn,dc=mydomain,dc=lan","enabled":1}
White screen and you have to press back and scroll through your users again.
An aphid as it works but annoying.
I am not a great fan of the new user manager when you are using it for a time the session can timeout but it just freezes it only till you do a refresh and your presented with the login.
The aphid happens when the zarafa account is disabled but is a groupware contact and you disable it.