Hi Alfonso,

I just encountered this error that you mention in the FAQ (Troubleshooting: CONN: Error using ==> spm_create_vol>create_vol. "unknown" is an unrecognised datatype (NaN). In my case I traced it back to the recent addition of the WFU PickAtlas to my matlab path, which includes an older and un-renamed version of the spm_type.m script that doesn't allow for the precision specification 'float32' used in conn_process. This old version of spm_type wants just 'float' and returns NaN when given 'float32'.

I fixed the issue by pushing PickAtlas below SPM8 in my path. Perhaps an error throw early on if isnan(spm_type('float32')) would be worth adding too.

Best,
Brad