As a general principle, when cases are settled and judgments are entered, they are final, except for some fairly limited rights of appeal. Most people are of the opinion that if you do not like what a judge does you simply can appeal their decision. Usually, you have to do more than just show that the judge may be wrong. Often, the Court of Appeals will only reverse the trial judge if there was an “abuse of discretion.” The courts are even more reluctant to set aside a settlement.
One exception to that rule which makes an appeal difficult is if one party committed fraud. The party against whom the fraud was committed may have recourse. This is consistent with fair play. If people can come out ahead by lying, it greatly increases the temptation to do so. Recently, there was a case in Michigan where a husband tried to set aside a property settlement based on fraud or mutual mistake, either of which can sometimes be a basis for setting aside a settlement.
In this particular case, the real property retained by the husband turned out to be overvalued by $10 million. It was overvalued because of fraud. However, the fraud was not a fraud committed by his wife, rather a business partner prior to the divorce. The court refused to set aside the settlement because it was not the wife who was the fraudulent party.