we should in fact remove the deterministic fiber tracking module from Lead-DBS because it is a very basic, even tensor based method (https://www.mathworks.com/matlabcentral/fileexchange/21130-dti-and-fiber-tracking) that hasn’t been used in a while. It is well possible that the method is broken.
Please try to run the GQI method instead which uses Fang-Cheng Yeh’s / DSI studio’s generalized q-sampling imaging and supports multishell data (such as from HCP). It is also deterministic and performed best in a recent open competition (http://biorxiv.org/content/early/2016/11/07/084137).
For multishell data, this is clearly the method of choice of the ones implemented in Lead-DBS.