I got the follwing error message when running the model estimation function using SPM.mat files. SPM5: spm_spm (v$Rev: 649 $) 15:56:22 - 24/08/2007 ======================================================================== Initialising parameters : ...done Output images : ...initialisingError running job: Error using ==> spm_create_vol (create_vol) "unknown" is an unrecognised datatype (NaN). -------------------------- Done. It runs through the process as normal and then gets to the 'writing' stage and the error message above appears. Given that this has just occurred with this subject (i.e. has been fine with the previous 11 subject's data) is there perhaps a problem with the files being accessed in the previous stages?