hi, it seems to me that in spm_cfg_eeg_convert.m, line 37 should read: usetrials.val = {1}; % instead of usetrials.val = {0}, to match the default value defined in spm_eeg_convert.m (from the help text: % S.usetrials - 1 - take the trials as defined in the data [default] % 0 - use trial definition file even though the data is % already epoched) Then, having corrected that, i get the following error: SPM8: spm_eeg_channelselection (v2866) 15:22:55 - 19/06/2009 ======================================================================= Failed 'M/EEG Conversion' Invalid MEX-file 'P:\Science\Matlab\spm8\@file_array\private\mat2file.mexw64': Invalid access to memory location. . In file "P:\Science\Matlab\spm8\@file_array\subsasgn.m" (v1355), function "subfun" at line 132. In file "P:\Science\Matlab\spm8\@file_array\subsasgn.m" (v1355), function "subsasgn" at line 73. In file "P:\Science\Matlab\spm8\spm_eeg_convert.m" (v3088), function "spm_eeg_convert" at line 346. In file "P:\Science\Matlab\spm8\config\spm_cfg_eeg_convert.m" (v3059), function "eeg_convert" at line 231. The following modules did not run: Failed: M/EEG Conversion Thanks for any help, regards, jakob