I have zenworks 2017 and windows 1703. After a few logins zenworks isn't usable. If you click on ZAPP in the lower right in red it says "Waiting for ZENworks agent to do initial refresh". It doesn't do anything from there. I've seen it sometimes go past this point but can take from 5 to 30 minutes. I didn't really see anything in the log that stands out and it shows that zenworks is doing stuff long after it's logged in. other odd things. if you right click on the Zenworks icon in the system try everything is grayed out except Check for updates and help.