Hey Rick,

Thanks for responding - I used all of those options and did combine the data (-combine_method OC). If I run without the -regress_anaticor_fast flag, I get combined datasets, stats etc with no problem.

To be certain it wasn't a multiple run issue, I just ran it again, with only one run and the same error is returned - the anaticor regressor is being calculated from the uncombined data, leading to it having 3x the number of timepoints.

Based on the anaticor section of the generated script, it appears that afni_proc's rm.all_runs dataset is being incorrectly generated by combining all of the volreg output - which is uncombined data:

# fast ANATICOR: generate local WMe time series averages
# create catenated volreg dataset
3dTcat -prefix rm.all_runs.volreg pb03.$subj.r*.volreg+tlrc.HEAD

When a combine block is included, shouldn't afni_proc generate something like the following code instead?:

# fast ANATICOR: generate local WMe time series averages
# create catenated volreg dataset
3dTcat -prefix rm.all_runs.volreg pb04.$subj.r*.combine+tlrc.HEAD

Though perhaps rm.all_runs.volreg+tlrc should then be renamed rm.all_runs.combine+tlrc, for accuracy.