If you are using the SF CheckedTreeView, then the only option you have at the moment.  This control was added to extend this type of functionality.  You may just want to use a regular TreeView control and turn on check boxes.

I'm using the SF CheckedTreeview. When I check a node, it affects all the nodes in related that the checked node. I.e. if it I uncheck a parent, it unchecks all the child nodes and updates the parent node as well. I need this to NOT happen. I want only the bottom level child nodes to change. Up level, they can display what happening, but can't affect the child nodes.

Handle the StateChanged event.  If a particular node is not allowed to be changed, set the value back to your liking.

I would like to be able to not allow the user to change the state of the checked state in a checkedtreeview. Is there any way to do that? I.e. if the user clicks the checkbox, it is ignored for specific nodes.