Proprietary Format
A proprietary format is a file or data structure whose specification is owned and controlled by a single party, often undocumented or restricted, so that reliably reading it depends on specific software rather than an open public standard.
Proprietary format refers to a way of encoding electronic records whose internal structure is controlled by a vendor or developer rather than defined by a published, openly governed standard. Reading or rendering the file may require particular software, a paid license, or knowledge that the owner does not fully disclose. This matters in recordkeeping because records frequently must remain authentic, readable, and usable for years or decades, well beyond the life of any single application. When a record is locked in a proprietary format, an organization risks technological obsolescence: if the software is discontinued or the license lapses, the record can become inaccessible even though the bits survive. For long-term preservation, records professionals favor open, well-documented formats and may migrate or normalize content on transfer. The distinction is concrete: a word-processing file tied to one program is proprietary, while a plain-text or openly specified document format can be opened by many independent tools. Modern electronic records guidance, including the move from the revoked endorsement of older recordkeeping criteria toward universal requirements, stresses format sustainability, exportability, and avoiding lock-in.