It was the second major search after Australia, China and Malaysia ended a fruitless search across an area of 120,000 sq km (46,332 sq miles) past year. However, investigators say they are confident the aircraft was deliberately flown off course and into the Indian Ocean.
The report highlighted shortcomings in the Malaysian government's response that exacerbated the mystery.
Dr. Kok Soo Chon, the lead investigator, told reporters at a press conference on the report that the men exhibited "no anxiety or stress".
Sarah Nor, the mother of Norliakmar Hamid, a passenger on missing Malaysia Airlines flight MH370, cries after she attended a briefing on the final investigation report on missing flight MH370. "No matter what we do, we can not exclude the possibility of a third person or third party or unlawful interference".
Captain Zaharie Ahmad Shah was flying the plane when it disappeared. "They have to continue the search until they find the plane", she said.
Investigators say they considered more than 60 theories about what could have happened to the plane.
Minister Anthony Loke Siew Fook said his ministry will take appropriate improvement measures and take action against any misconduct committed based on the findings under the existing provisions of the law.
Similarly, the plane's loss of communications before veering off track was more likely due to systems "being manually turned off or power interrupted to them" than a malfunction, it said.
It said without the benefit of the examination of the aircraft wreckage and recorded flight data information, "the investigation was unable to identify any plausible aircraft or systems failure mode that would lead to the observed systems deactivation, diversion from the filed flight plan route and the subsequent flight path taken by the aircraft".
MH370's cargo included 221 kilograms (487 pounds) of lithium batteries and 4.6 tons of fresh mangosteen fruit, according to its manifest.
Overall the safety investigators found most fault with the air traffic controllers, first in Kuala Lumpur and then Ho Chi Minh City, who were meant to be watching the plane but who had not followed protocol, meaning the plane was off radar for about 20 minutes before anyone was alerted. It showed there were only two attempted phone calls made to the aircraft from the ground, four to five hours apart.
Newly elected Prime Minister Mahathir Mohamad said Malaysia will consider resuming the search for MH370 only if new clues came to light.
A 120,000 sq km area in the southern Indian Ocean was searched by officials in Australia, China and Malaysia a year ago at a cost of £112million.
In all, 27 pieces of aircraft debris have been collected from various places around the world but only three wing fragments that washed up along the Indian Ocean coast have been confirmed to be from MH370.
Theories range from mechanical error or a remote-controlled crash, to more freaky explanations like alien abduction and a Russian plot. But that search was called off after failing to locate the plane while scouring 125,000sq km of the Indian Ocean.