fMRIPrep breaking before generating reports and --reports-only failing

Summary of what happened

Hello everyone,

I’m running fmriprep (v24.1.1) on an HCP cluster in a dataset with ~350 participants. From these, only 23 participants finished successfully, and the rest finished the fmriprep process but had an error when creating the reports. I am trying to run fmriprep with the `–reports-only` flag, and it still fails. In both cases, the last line of the error points towards a different participant.
Do you have any idea of what might be creating the problem and how to fix it?

Thank you

Command used (and if a helper script was used, a link to the helper script or the command generated)

  • For the first run
export APPTAINERENV_TEMPLATEFLOW_HOME=${proj_path}/templateflow
export APPTAINER_BINDPATH=$APPTAINERENV_TEMPLATEFLOW_HOME
export APPTAINER_BIND=${proj_path},${input},${output_fmriprep},${output_fmriprep}/logs,$APPTAINERENV_TEMPLATEFLOW_HOME

singularity run --cleanenv -B ${proj_path}:/scratch -B $APPTAINERENV_TEMPLATEFLOW_HOME ${proj_path}/fmriprep-24.1.1.simg \
    ${input} ${output_fmriprep} participant \
    --participant-label ${SUBJECT} \
    --skip_bids_validation \
    --nthreads 16 \
    --omp-nthreads 16 \
    --low-mem \
    --longitudinal \
    --output-spaces anat MNI152NLin2009cAsym:res-2 \
    --fs-license-file ${proj_path}/fs_license.txt \
    --fs-no-reconall \
    --output-layout bids \
    --work-dir ${output_fmriprep}
  • For --reports only
export APPTAINERENV_TEMPLATEFLOW_HOME=${proj_path}/templateflow
export APPTAINER_BINDPATH=$APPTAINERENV_TEMPLATEFLOW_HOME
export APPTAINER_BIND=${proj_path},${input},${output_fmriprep},${output_fmriprep}/logs,$APPTAINERENV_TEMPLATEFLOW_HOME

singularity run --cleanenv -B ${proj_path}:/scratch -B $APPTAINERENV_TEMPLATEFLOW_HOME ${proj_path}/fmriprep-24.1.1.simg \
    ${input} ${output_fmriprep} participant \
    --participant-label ${SUBJECT} \
    --skip_bids_validation \
    --reports-only \
    --fs-license-file ${proj_path}/fs_license.txt \
    --work-dir ${output_fmriprep}

Version

24.1.1

Environment (Docker, Singularity, custom installation)

Docker in HCP

BIDS Validity (could generally say “Are your data formatted according to a validatable standard? Please provide the output of the validator.”)

Data is validated

Relevant log outputs (maybe prompt for 20 lines)

  • For the first run (Running for participant sub-06VPJN)
260309-20:13:56,605 nipype.workflow INFO:
	 [Node] Finished "ds_bold", elapsed time 91.114476s.
2026-03-09 20:13:56,605 [    INFO] [Node] Finished "ds_bold", elapsed time 91.114476s.
260309-20:13:59,742 nipype.workflow IMPORTANT:
	 fMRIPrep finished successfully!
2026-03-09 20:13:59,742 [IMPORTANT] fMRIPrep finished successfully!
260309-20:13:59,749 nipype.workflow IMPORTANT:
	 Works derived from this fMRIPrep execution should include the boilerplate text found in <OUTPUT_PATH>/logs/CITATION.md.
2026-03-09 20:13:59,749 [IMPORTANT] Works derived from this fMRIPrep execution should include the boilerplate text found in <OUTPUT_PATH>/logs/CITATION.md.
Traceback (most recent call last):
  File "/opt/conda/envs/fmriprep/bin/fmriprep", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/cli/run.py", line 228, in main
    failed_reports = generate_reports(
                     ^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/reports/core.py", line 100, in generate_reports
    report_error = run_reports(
                   ^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/reports/core.py", line 43, in run_reports
    robj = Report(
           ^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/nireports/assembler/report.py", line 327, in __init__
    self.index(settings)
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/nireports/assembler/report.py", line 350, in index
    layout = BIDSLayout(
             ^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/layout.py", line 177, in __init__
    _indexer(self)
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 148, in __call__
    all_bfs, all_tag_dicts = self._index_dir(self._layout._root, self._config)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 239, in _index_dir
    dir_bfs, dir_tag_dicts = self._index_dir(d, config, force=force)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 208, in _index_dir
    _, dirnames, filenames = next(path.fs.walk(path.path))
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
StopIteration: ('<path_to_output_folder>/fmriprep/sub-1PPFYF', [], [])
  • For --reports-only (Running for participant sub-06VPJN)
2026-03-20 15:55:37,865 [IMPORTANT] Running fMRIPrep version 24.1.1

         License NOTICE ##################################################
         fMRIPrep 24.1.1
         Copyright The NiPreps Developers.
         
         This product includes software developed by
         the NiPreps Community (https://nipreps.org/).
         
         Portions of this software were developed at the Department of
         Psychology at Stanford University, Stanford, CA, US.
         
         This software is also distributed as a Docker container image.
         The bootstrapping file for the image ("Dockerfile") is licensed
         under the MIT License.
         
         This software may be distributed through an add-on package called
         "Docker Wrapper" that is under the BSD 3-clause License.
         #################################################################
260320-15:55:38,9 nipype.workflow IMPORTANT:
         Running --reports-only on participants 06VPJN
2026-03-20 15:55:38,009 [IMPORTANT] Running --reports-only on participants 06VPJN
Process Process-2:
Traceback (most recent call last):
  File "/opt/conda/envs/fmriprep/lib/python3.11/multiprocessing/process.py", line 314, in _bootstrap
    self.run()
  File "/opt/conda/envs/fmriprep/lib/python3.11/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/cli/workflow.py", line 94, in build_workflow
    failed_reports = generate_reports(
                     ^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/reports/core.py", line 100, in generate_reports
    report_error = run_reports(
                   ^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/fmriprep/reports/core.py", line 43, in run_reports
    robj = Report(
           ^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/nireports/assembler/report.py", line 327, in __init__
    self.index(settings)
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/nireports/assembler/report.py", line 350, in index
    layout = BIDSLayout(
             ^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/layout.py", line 177, in __init__
    _indexer(self)
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 148, in __call__
    all_bfs, all_tag_dicts = self._index_dir(self._layout._root, self._config)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 239, in _index_dir
    dir_bfs, dir_tag_dicts = self._index_dir(d, config, force=force)
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/envs/fmriprep/lib/python3.11/site-packages/bids/layout/index.py", line 208, in _index_dir
    _, dirnames, filenames = next(path.fs.walk(path.path))
                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
StopIteration: ('<path_to_output_folder>/fmriprep/sub-SXGP7U', [], [])

Screenshots / relevant information

Hi @albrzez,

Please do not set your working directory the same as your output directory. Also recommend updating fMRIPrep. Also, fs-no-reconall is also not recommended.

Best,

Steven