Define the discrepancy
The difference may concern a missing message, changed text, attachment versions, timestamps or conversation ordering. Preserve both supplied sets separately and identify how each was obtained. A printout, selected export and complete mailbox collection are not equivalent representations.
Sources and comparison
Native messages, collection settings, related correspondence and available independent records can help explain the difference. The comparison should examine content and structure rather than rely solely on subject lines, visible thread order or message counts. Retain the original timestamp values and offsets alongside any common analysis timezone.
Limits and deliverable
Different hashes may result from export format or added headers. Matching Message-ID values can assist comparison but do not establish an unaltered or complete record on their own. Missing items can reflect collection limitations. A suitable output is a discrepancy schedule with source references, matching criteria, alternative explanations and unresolved questions. Begin with the disputed messages and the history of each supplied collection. The instruction should specify whether the task is reconciliation, authenticity assessment or both, as these require different conclusions.