I think that I have resolved the bvecs error by using sudo nano option but now in the next step I visualize this error:<div><br></div><div><div>ERROR: fio_pushd: /Applications/freesurfer/subjects/subject_prova/Diff01/dlabel/mni</div><div>ERROR: must specify brain mask volume for output subject</div></div><div><br></div><div>Thanks,</div><div><br></div><div>Stefano</div>