A patent application is only examined as to formal requirements. The applicant is informed of any formal errors found, as well as a deadline for correcting any errors. If the errors are not corrected in good time or properly, the application will lapse. In the report on the novelty search carried out by the authorities (which is provided about nine months after first filing) a list is provided with possibly damaging literature. A first substantive opinion is also provided. Neither the search report nor the substantive opinion necessarily mean that the application must be amended. Even in the case of a negative search report and/or a negative first substantive opinion the Dutch patent can be granted without further amendment of the application.
The validity of a patent can be challenged after grant of the patent in possible legal proceedings. A court can then form an opinion as to whether a patent has been rightly granted or not. Depending on the evidence submitted against the patent, the court can in an extreme case (partially) revoke a patent.