Finds and deletes all unknown references within the maya scene.

maya_kill_unknown_referencenodes.py

import maya.cmds as cmds


def check_unknown_refs():
    """
    Checks unknown references.

    :return: unknown_references: list of all unknown references within the scene.
    """

    all_references = cmds.ls(type='reference')

    unknown_references = []
    for ref in all_references:
        try:
            ref_path = cmds.referenceQuery(ref, filename=True)
        except RuntimeError:
            unknown_references.append(ref)

    return unknown_references


def delete_unknown_refs(unknown_references):
    """
    Unlocks and deletes all unknown reference nodes.

    :return:
    """

    for ref in unknown_references:
        cmds.lockNode(ref, lock=False)
        cmds.delete(ref)


if __name__ == '__main__':
    delete_unknown_refs(check_unknown_refs())