In a statement after attending a meeting of oversight body the Northern Ireland Policing Board, Mr Byrne said he gave an update on the service's immediate response, the criminal investigation and "approach to begin recovery".
"It was a constructive meeting," he said.
"I recognise the gravity of the situation and the challenges ahead.
"The independent review led by Assistant Commissioner O'Doherty, City of London Police, will provide answers to the questions.
"The service executive team and I are grateful for the support of the board.
"I would also reiterate my thanks to officers and staff who continue to serve the public around the clock."
TUV vice chair Allister Kyle was critical that the PSNI were co-commissioners of the review: “The Policing Board missed an obvious opportunity to assert its independence by taking exclusive ownership of the review into the catastrophic data breaches in the PSNI.
"Instead, it is jointly seeking the review with those it claims oversight over, rather than demonstrably showing independence in thought and deed.
“Thus, in accordance with such review processes, the PSNI is likely to get advance sight of the report and have the opportunity to make representations thereon, before publication.
“Such is not a confidence-building approach, but then this is a board seemingly desperate to retain a failed chief constable in office.”
Mike Nesbitt, Ulster Unionist representative on the Policing Board, called on the chief constable and his senior colleagues to act immediately to form a plan to improve the appalling levels of low confidence in the PSNI.
He said it was of major concern that “we are no longer delivering the new beginning in policing, as promised in the 1999 report of the Independent Commission on Policing for Northern Ireland, commonly known as Patten”.
He said the the number of Protestants and Catholics expressing satisfaction with the police. had nearly halved.