Environment
Novell ZENworks 10 Configuration Management with Support Pack 1 - 10.1
Situation
zac unr -f requires Administrator user name and password even when unregistering locally.
Resolution
This is fixed in version 10.2 - see KB 7003225 "ZENworks 10 Configuration Management 10.2" which can be found at https://www.novell.com/support
In 10.2 there is a new -s option to suppress prompt for Administrator and password when unregistering locally only.
Use:
zac unr -f -s
To unregister locally and suppress prompt.
Additional Information
Note: Unregistering always requires local Windows Administrator rights.
Using -f without -s will unregister from the zone, if available, or locally if not. Use of -s implies local only.