Vast amounts of data stored by the Australian Taxation Office have been lost in the crash that brought down the agency's internal systems and customer service websites on Monday and Tuesday.
Large numbers of ATO officials were still sitting idle on Tuesday afternoon, unable to use their computers for a second day in the latest public service tech meltdown.
Fairfax has been told that it may be Wednesday before the Tax Office's systems are fully restored and that the ATO is trying to recover a petabyte – a million gigabytes – of data.
It is unclear what was recorded on the lost data but Tax Office management are adamant that no taxpayer information has been compromised.
The ATO revealed on Tuesday that the crash, which has brought much of the Tax Office's work to a halt, was caused by a computer hardware system that was upgraded just 13 months ago.
The systems first crashed late on Sunday night or early Monday morning, and were still down on Tuesday evening, despite the frantic efforts of the ATO's IT teams and the Hewlett Packard contractors who supplied the systems.
All ATO external websites, client portals and tax agent portals, AusKey, ATO online, where taxpayers undertake their self-help transactions, remained unavailable and maintenance pages are up.
Many internal processing systems for staff were offline as well.
Systems that move and allocate cases are not working and actual processing systems were not available either, with the outages hitting across the 19,000-strong agency.
Casual staff who showed up for work processing tax returns on Monday morning were sent home and those working afternoon shifts were told not to come to work.
"The ATO is working closely with our external service provider Hewlett Packard Enterprise (HPE) to resolve the issues with our online services, portals and website," the ATO's acting chief information officer Steve Hamilton said.
"No taxpayer information has been compromised.
"Specialist engineers have been working through the night with ATO staff to rectify the outages."
Mr Hamilton said the crash had not been caused by old ageing equipment.
"These outages relate to a hardware storage solution that was upgraded in November 2015 – it is not old equipment," he said.
"Our primary back-up systems, that should have kicked in immediately, were also affected.
"We understand this is the first time this problem has been encountered anywhere in the world and we are working with HPE to determine the underlying cause.
"While these investigations are ongoing, we have had to implement alternative recovery procedures that are taking longer to complete.
"At this stage, we are working towards critical systems such as the Tax Agent Portal and ATO.gov.au being available later today."
The latest public service IT failure comes after the Prime Minister's departing digital guru took a parting shot at the service's digital efforts, its "remarkable" over-dependence on outsourcing and a culture of "blame aversion".
Paul Shetler said the history of the federal government digital failure underlines the need for the public service to train its own workers and end its reliance on expensive and wasteful private sector outsourcing.
Mr Shetler also took a swipe at the Canberra mandarins who were resisting change and needlessly complicating the digital transformation agenda.
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