Hi The following error occurs when estimating a second level model. *...use the results section for assessment ESS image 1 : ...written ess_0001.img spm{F} image 1 : ...written spmF_0001.img ESS image 2 : ...written ess_0002.img spm{F} image 2 : ...written spmF_0002.img Failed 'Model estimation' In an assignment A(:) = B, the number of elements in A and B must be the same. In file "/home/joe/spm8/config/spm_run_fmri_est.m" (v3327), function "spm_run_fmri_est" at line 77. The following modules did not run: Failed: Model estimation* Does anyone know the cause, and how to fix it? Thanks. Regards Joe -- Joseph Whittaker, M.Sc Ph.D Student G.803 Neuroscience and Psychiatry Unit Stopford Building University of Manchester Oxford Road Manchester, UK Tel: 0161 275 1729