Perhaps, as Çetin explained, you turn on buffering too late. You should do it in Form.Load(), at the latest (the other option, I think, is some method in the Form's DE - but I never used that). Form.Init() is not appropriate.

Or perhaps you are still turning buffering off again?

When saving records, don't forget to check for the return value of TableUpdate(). Here is some sample code:

Form.OnSave()
if TableUpdate()
  return .T.
else
  local laError(1)
  aerror(laError)
  MessageBox("Error saving record, message #" + trans(laError(1) + "-" + laError(2))
  return .F.
endif

This is just the skeleton; the actual method would probably have some additional details.