Dear All, I'm using the most recent version of SPM8 and ran into this error during the model estimation step. The data set (two sessions) is re-aligned, resliced and smoothed. Thanks and Regards, Sheeba ---------------------------- Failed 'Model estimation' Output argument "V" (and maybe others) not assigned during call to "/software/spm8/spm_reml.m (spm_reml)". In file "/software/spm8/spm_spm.m" (v3151), function "spm_spm" at line 876. In file "/software/spm8/config/spm_run_fmri_est.m" (v2928), function "spm_run_fmri_est" at line 69. The following modules did not run: Failed: Model estimation