I'm getting the following error when preprocessing functional scans, during the functional normalization step. I'm trying to import raw functional data from a few dozen subjects, all with essentially identical scans, and this error pops up for about 1/3 of them. I haven't noticed any patterns that distinguish this third from the other subjects. Occasionally the error stops the whole stream, whereas other times if I wait longer, it will continue to work, eventually telling me that preprocessing has finished correctly.  Anyone have any ideas?  Is there a place to see the file names or extensions that each processing step is supposed to create? I'm not sure where the "meaneasting_state" extension is supposed to come from. Thank you so much!

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Error using conn_setup_preproc (line 979)
Error preparing files for normalization. Mean functional file C:\...\fMRI DATA\TimePoint_1\dn_p004_tp1_meanesting_state.nii not found

Error in conn (line 806)
ok=conn_setup_preproc('',varargin{2:end});
Error in conn_menumanager (line 119)
feval(CONN_MM.MENU{n0}.callback{n1}{1},CONN_MM.MENU{n0}.callback{n1}{2:end});
CONN v.17.a
SPM12 + DEM FieldMap MEEGtools
Matlab v.2015b
storage: 732.9Gb available