that's a pretty large defect - about 15% of the size of a typical surface. The defect correction complexity is quadratic in the convex hull of the defect, so it can take a *long* time for big defects. Usually one this big means something went badly wrong - a bunch of skull attached, or cerebellum left over. Check the wm.mgz and the ?h.inflated.nofix to see if something lik ethat happened (probably near the back of the brain as vertex numbering goes back to front, so the first defect will be near the occipital pole)

cheers Bruce

On Mon, 23 Apr 2018, Z Hessam wrote:

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Hello FreeSurfer Team i have problem when run a data set, i re-run it but that error remain (just "convex hull" changed from 6148 to 6147!!)

this is the last line in terminal (that process doesn't exceed that after about 10 hours!!!)

"CORRECTING DEFECT 0 (vertices=21958, convex hull=6147, v0=0)"

but the first time i run this data set, there was more another line in terminal:

"XL defect detected ..."

now i want to know why this error occurred ? and what should i note in my data to never encounter this error again?

(I read some similar mails, but i didn't understand my questions)

thanks a lot again for your attention