The Diversity Lottery (DV lottery) has specific rules. Often immigration attorneys are forced to sue USCIS if it gets close to the September 30th deadline to act on the application because it would cause immediate and irreparable harm. The applicant needs to receive their green card before September 30th of the DV lottery year.
On occasion we needed to go in front of a judge and argue that our client needs to have a US CIS interview or they would suffer serious harm because of the September 30thdeadline, and, usually the judge orders the government to proceed with the I – 485 (application for permanent residence/green card) interview.
We can sue the USCIS because there will be an irreparable harm to the lottery winner if the green card is not issued by September 30th as the application becomes void and there is no chance to receive green card even if you can prove that immigration made a mistake in your application.
For example, even if you have a letter from USCIS saying that they lost your file and that is why they could not give you a green card you would still lose the case because the law is very clear the DV green card needs to be issued by September 30th or the application becomes void.