Guidance needed: ExploreASL v1.11 BIDS2Legacy error (“bids2legacy” field missing)

[Kajuboju Tejaswi]

Dear ExploreASL community,

I hope you are all doing well. My name is kajuboju Tejaswi, and I am currently working with arterial spin labeling (ASL) MRI data using ExploreASL v1.11.0. I am writing to kindly seek guidance regarding an issue I am encountering during the BIDS processing stage.

I am working with a BIDS-compliant dataset (63 subjects), organized according to the ExploreASL manual, with rawdata/sub-XX/anat and rawdata/sub-XX/perf folders, appropriate JSON files, and a valid dataset_description.json at the study root. I am running ExploreASL using the standard manual-recommended command: ExploreASL('StudyDir');

  However, during the BIDS → Legacy conversion, the pipeline consistently stops with the following error: Reference to non-existent field 'bids2legacy'

No subjects found, x.SUBJECTS was empty

This occurs even after fully deleting the derivatives/ExploreASL folder, restarting MATLAB, and carefully rechecking the BIDS structure and filenames.

I would be very grateful if anyone could advise whether this is a known issue in ExploreASL v1.11, or if there are additional checks or requirements for successful BIDS2Legacy conversion that I may be overlooking.

Thank you very much for your time and for your support of the ExploreASL community.  

[ExploreASL]

Try updating to the "develop" branch. Also try deleting the "derivatives" directory and "dataPar.json" to make sure you do not set a filter on subject name. 

Have you tried a BIDS validator to make sure your filenames are OK? Can you post a screenshot of your directory and files so that I can double-check if everything is fine.

Thanks,
Jan