From useradd(8) man page -o, --non-unique <snip> This option is only valid in combination with the -o option. There should be '-u' instead of '-o'. Invocation of useradd with -o without -u gives correct warning: useradd: -o flag is only allowed with the -u flag Version-Release number of selected component (if applicable): shadow-utils-4.1.4.2-13.fc15
shadow-utils-4.1.4.3-10.fc16 has been submitted as an update for Fedora 16. https://admin.fedoraproject.org/updates/shadow-utils-4.1.4.3-10.fc16
Package shadow-utils-4.1.4.3-10.fc16: * should fix your issue, * was pushed to the Fedora 16 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing shadow-utils-4.1.4.3-10.fc16' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2011-15737 then log in and leave karma (feedback).
shadow-utils-4.1.4.3-10.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.