thrives, a court is unlikely to completely enforce it. Failure to disclose all property, finances, or financial obligations at the time of execution. If bank accounts, property, or obligations are found to have existed at the time of the marriage but were not included in the agreement, the entire agreement will be invalid, and all property, including the additional assets, will be subject to division. The original document was not filed correctly. If the agreement was not properly and legally documented and witnessed, it is invalid. Performing an action stated within a restrictive clause. When executing a prenup, both parties can include restrictive clauses that invalidate the agreement if performed. For example, an infidelity clause will invalidate an agreement if one spouse has an extramarital affair.