Preventing duplicate ICL files and/or ICL file elements, including duplicate ICLs, items, and item bundles, from being processed for payment and/or presentment. A duplicate detection module can assign a predictable and repeatable unique identifier to each ICL file and/or ICL file element. The duplicate detection module can determine whether each ICL file and/or element is a duplicate by comparing the identifier associated with the ICL file and/or element with information stored in a record of already processed files/elements. In response to determining that an ICL file and/or element is a duplicate, the duplicate detection module can determine not to process the file/element for payment and/or presentment. In response to determining that the ICL file and/or element is not a duplicate, the duplicate detection module can store information regarding the file/element in the record. For example, the stored information can include the unique identifier associated with the file/element.