fMRIPREP: ValueError: A fieldmap or phase-difference estimation type was found, but an anatomical reference (magnitude1 file) is missing

Hi,

I tried to run fMRIPrep with fieldmap correction however, I experienced the following error(s):

FileNotFoundError: File path </data/sub-ER006/ses-1/fmap/sub-ER006_ses-1_acq-1_magnitude1.nii> does not exist, is a broken link, or it is not a file

ValueError: A fieldmap or phase-difference estimation type was found, but an anatomical reference (magnitude1 file) is missing

This is the related directory:
sub-ER006_ses-1_acq-diff_magnitude1.nii
sub-ER006_ses-1_acq-fmri_magnitude1.nii
sub-ER006_ses-1_acq-diff_magnitude2.nii
sub-ER006_ses-1_acq-fmri_magnitude2.nii
sub-ER006_ses-1_acq-diff_phasediff.json
sub-ER006_ses-1_acq-fmri_phasediff.json
sub-ER006_ses-1_acq-diff_phasediff.nii
sub-ER006_ses-1_acq-fmri_phasediff.nii

I know that sub-ER006_ses-1_acq-1_magnitude1.nii doesn’t exist (as per the first error), however I’m unsure on why its trying to locate a file under this name in the first place?

Many thanks in advance!
Phoenix

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