Hi all, I’m trying to provide epi_reg with a WM mask of the T1w image, but it seems epi_reg is trying to invoke FSLeyes, and failing. I was wondering wether anybody stumbled into the same problem. I’m running epi_reg locally on macOS, FSL version 5.0.9. Here is some pseudo-code (all images/files exist and are readable): epi_reg \ --epi=${funcImg}_restore_brain \ --t1=$structImg \ --t1brain=${structImg}_brain \ --out=$tmpDir/func_2struct_epireg \ --wmseg=$studyDir/$subj/structural/WM \ --fmap=$fieldMap \ --fmapmag=$magnImg \ --fmapmagbrain=${magnImg}_brain \ --echospacing=0.000404998 \ --pedir=y And this is the output: /Applications/FSLeyes.app/Contents/MacOS//python: /Applications/FSLeyes.app/Contents/MacOS//python: cannot execute binary file Cannot open volume /func_2struct_epireg_fast_wmseg for reading! epi_reg will continue and try to run the bbr nonetheless, but this isn’t exactly my intended behaviour. If it makes a difference, FSLeyes (0.9.6) is working fine on my computer. Any ideas? Much appreciated. cheers, Lennart