In my environment we have seen a few workstations, maybe a dozen out of 1400, that do not log into Zenworks automatically. These workstations can log in manually no problem but it has to be done by right clicking the ZenNotifyIcon and selecting login.

I have searched for TIDs and this forum for this problem and have found a few good posts but nothing that has corrected my issue. I found the posts about turning on the logging for NWGina and the like, and that has helped me find my problem.

In my case I found the log entry:
[16:13:43:171] [NWGINA-360-364] DetectInstalledZENVersion entered
[16:13:43:187] [NWGINA-360-364] RegQueryValueEx Failed: 2
[16:13:43:281] [NWGINA-360-364] DetectInstalledZENVersion returning ZENNotSupported

I tracked this down to a missing registry key:

The version key was missing on the effected workstations. After adding the key and rebooting, the system logs into Zen automatically.