I'm not sure what you mean by "scheduled network discovery" - can you explain a bit more what it is you're trying to do? Whereabouts in 3.6.1 was this configured?
Discovers new devices that get added to the network; workstations and servers
This sounds like Rogue System Detection, but it's not something that you schedule: you deploy a sensor and it reports back to the server.
Unless you're talking about an Active Directory import or sync? In which case that's configured in the synchronisation settings for the system tree group in question.
Yes I am talking about active directory sync I can't find a way to schedule that. I can only do it manaully
You can set up a server task to sync AD on a schedule. When configuring the task, you have the option to sync as many of the system tree locations where you have set up AD as a sync type.
Hope this helps.