Comment 3 for bug 230466

When you join a domain, likewise-open makes changes to the following files (making in-place backups with an .lwidentity.orig suffix):
/etc/ssh/sshd_config
/etc/ssh/ssh_config
/etc/nsswitch.conf
/etc/hosts
/etc/krb5.conf
/etc/security/pam_lwidentity.conf
/etc/pam.d/common-account
/etc/pam.d/common-auth
/etc/pam.d/common-password
/etc/pam.d/common-session

The disruptive changes (the /etc/pam.d/ and nsswitch.conf files) are reverted when you leave a domain (using "domainjoin leave" command or the Leave option of the GUI). You can then uninstall the package and you can still login to the system.

If you uninstall likewise-open while those system files are still configured to use it (i.e. you're still in the domain), it's like if you uninstalled pam : the system will indeed be mostly unusable. The workaround is the one described by Froza.

Uninstalling should not be possible with a domain still joined ?