Fingerprints as input columns to KNIME’s 'Similarity Search' node are not recognized unless both input columns are named exactly the same. No errors are given; the column simply doesn't show up in the selectable list if doesn't have the appropriate name (even if the fingerprint types are identical). This is a minor inconvenience, and a workaround is to rename the fingerprint column before pulling data into this node. It would be nice if it allowed you to manually select both columns for comparison, the way it is done in chemical similarity nodes from other vendors.
Regards,
--George