Hello some structural scans failed segmentation and normalization after coregistering to RS fMRI scans that had been tilted forward (30 degrees on the x axis to avoid inferior-frontal dropout).  We used the unified segmentation method.  It seems SPM may not be able to match the structural to the standardized tissue templates if the orientation differs a lot.  We were able to resolve the problem somewhat by reorienting the images.  Has anyone else experienced this?