A proprietary file format is a file format of a company, organization, or individual that contains data that is ordered and stored according to a particular encoding-scheme, such that the decoding and interpretation of this stored data is easily accomplished only with particular software or hardware that the company itself has developed.
Proprietary formats are typically controlled by a company or organization for its own benefit, and the restriction of its use by others is ensured through patents or as trade secrets.
[citation needed] If the information is stored in a way which the user's software provider tries to keep secret, the user may store the information by virtue of having generated it, but they have no way to retrieve it except by using a version of the original software which produced the file.
Without a standard file format or reverse engineered converters, users cannot share data with people using competing software.
The issue of risk comes about because proprietary formats are less likely to be publicly documented and therefore less future proof.