When using LDAP login authentication domain\username is the format that we need to use but Joomla will not allow this. When trying to save these users in Joomla backend the format is rejected due to the backslash that is used between the domain and username for the "Login Name."
Save failed with the following error: Please enter a valid username. No space at beginning or end, at least 2 characters and must not contain the following characters: < > \ " ' % ; ( ) &
I would like to find a solution that does not require hacking the core so updates could still be done without having to re-modify the core.