Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 90, § 7N

Notwithstanding any disclaimer of warranty, a motor vehicle contract of sale may be voided by the buyer if the motor vehicle fails to pass, within seven days from the date of such sale, the periodic staggered inspection at an inspection station licensed pursuant to section seven W; provided, that the defects which are the reasons for the failure to issue a certificate of inspection were not caused by the abusive or negligent operation of the motor vehicle or by damage resulting from an accident or collision occurring after the date of the sale; and provided, further, that the cost of repairs necessary to permit the issuance of a certificate of inspection exceeds ten per cent of the purchase price of the motor vehicle.

In order to void a motor vehicle sale under this section the buyer shall, within fourteen days from the date of sale, notify the seller of his intention to do so, deliver the motor vehicle to the seller, provide the seller with a written statement signed by an authorized agent of such inspection station stating the reasons why the motor vehicle failed to pass the safety or combined safety and emissions inspection and an estimate of the cost of necessary repairs. The buyer shall be entitled to a refund of his purchase price unless the buyer and seller agree in writing that the seller may make the necessary repairs at his own cost and expense within a reasonable period of time thereafter. This section shall apply only to motor vehicles purchased for the immediate personal or family use of the buyer.