What is the procedure when the USPTO cannot locate a patent or application file?

When the USPTO cannot locate a patent or application file after a reasonable search, they follow the procedure outlined in 37 CFR 1.251. The key steps are:

1. The Office notifies the applicant or patentee about the unlocatable file.
2. A time period is set for the applicant or patentee to comply with the notice.
3. The applicant or patentee must respond by either:
   • Providing a copy of their record of all correspondence with the Office (except U.S. patent documents)
   • Producing their record for the Office to copy
   • Stating that they do not possess any record of the correspondence

As stated in MPEP 508.04, “37 CFR 1.251 sets forth a procedure for the reconstruction of the file of a patent application, patent, or any other patent-related proceeding that cannot be located after a reasonable search.”