Hi,

I have been running into the same errors while doing the T2 segment (SPM12). Followed your suggestions, I have increased the voxel size of the InVivo template and rat priors by 10, as well as set "no bias regularization"+"No Affine Registration". However, I am still running into the following segment failures:

SPM12: spm_preproc_run (v7670) 00:37:32 - 29/06/2020
========================================================================
Segment D:\t2.nii,1
29-Jun-2020 00:37:36 - Failed 'Segment'
Error using chol
Matrix must be positive definite.
In file "D:\spm12\spm_preproc8.m" (v7593), function "log_likelihoods" at line 929.
In file "D:\spm12\spm12\spm_preproc8.m" (v7593), function "latent" at line 969.
In file "D:\spm12\spm12\spm_preproc8.m" (v7593), function "spm_preproc8" at line 410.
In file "D:\spm12\spm12\spm_preproc_run.m" (v7670), function "run_job" at line 156.
In file "D:\spm12\spm12\spm_preproc_run.m" (v7670), function "spm_preproc_run" at line 41.
In file "D:\spm12\spm12\config\spm_cfg_preproc8.m" (v7629), function "spm_local_preproc_run" at line 474.

The following modules did not run:
Failed: Segment

Thanks,
hn