hmm...we've had these issues too. Lots of texture image paths are still in the asset tracker?
They are also still in the material editor.
There may be a better way, but here's what we do:
Open Slate material editor. Then Edit menu -> Clear View-> Yes. Switch to the Compact Material Editor. Then Utilities menu -> Condense Material Editor Slots. Switch back to the Slate editor and then Material menu -> Get all scene materials, should return no materials now. Now go to your asset tracker, hit refresh, and they should all be gone.
There have been times where objects and other items linger still in the asset tracker. If they are not actually in the scene, when you right click on them and choose set path, the system will clear out all of the unused items in the tracker including the one you right clicked.
