Where does knowledge get lost?
In many companies, valuable knowledge sits with a few people. How a particular file runs, what a customer asked for, where that one plan is: it is in a mailbox, a personal folder or simply in someone's head.
As long as those people are there, nobody notices. When someone leaves, or is ill for a few weeks, the search begins. Colleagues ring round, files stand still, and a new member of staff depends on others' explanations for weeks.
The problem is not that the knowledge is missing. It is just not in the place where the next person looks for it.