Preregistration is a procedure that may be available in some cases to protect against pre-publication infringement. It is optional. It is not a prerequisite to filing a copyright registration application.
To qualify for preregistration, the work must be unpublished and in the process of being prepared for commercial distribution. Preregistration is available only for motion pictures, sound recordings, musical compositions, book manuscripts, computer programs (including video games), and advertising or marketing photographs.
Preregistration is not a substitute for registration. A person who preregisters a work must register the work within one month after the copyright owner becomes aware of infringement, and not later than three months after publication.