If there is...
- no top management support for KM (includes their willingness to talk about the importance of KM when talking to the workforce)
- no Management/HR-driven culture of acknowledging knowledge sharers/mentors rather than individuals who accomplish but hoard
...KM will not work!
You can as well get ready to see 80% of your effort going down the drain. It is indeed the pareto rule at work. 80% of KM will arguably happen if there is just 20% in place - management support and a culture that pampers those who share. The KM's job is a lot easier then....(she of course then needs to work on improving those processes, communicating effectively, making the technology fascinating, evangelizing et al)