The report however highlighted mistakes and protocols and guidelines that were not followed, the families told reporters after a briefing on the report.
The report will be released to the media at 0630 GMT.
"We hope that these mistakes will not be repeated and that measures are put in place to prevent them in the future," said Grace Nathan, a lawyer whose mother, Anne Daisy, was on the plane.
Flight MH370, carrying 239 people, disappeared on its way from Kuala Lumpur to Beijing on March 8, 2014. It is one of the world's greatest aviation mysteries.
The report comes two months after Malaysia called off a privately funded underwater search for the aircraft.
(Reporting by Rozanna Latiff; writing by Praveen Menon; Editing by Nick Macfie)