🗂️ Almost three years of internal government chat messages just vanished. Roughly 7.5 million of them. Some were casual "did you see this email?" pings. Others were the kind of message that counts as an official public record. And a chunk of those can't be brought back. The cause wasn't a hacker or a hard-drive crash, but a routine maintenance job that quietly went sideways.

Three years of chat, erased during a settings change

On June 12, Japan's Ministry of Health, Labour and Welfare (known as MHLW), the sprawling ministry that handles health, pensions, labor and welfare for the whole country, disclosed that a batch of internal chat data had been wiped from its in-house network.

The app in question was Microsoft Teams, used by staff for day-to-day coordination across the ministry. According to the announcement, messages and files sent between January 4, 2023 and October 29, 2025, about two years and ten months' worth, were deleted. Kyodo News put the figure at roughly 7.5 million items.

The data is gone for good rather than leaked. The ministry stressed that nothing was exposed to outsiders and that no personal information escaped; the records were simply erased. But not everything could be recovered, and the part that couldn't includes chats that qualify as administrative documents: in other words, official records of government business.

MHLW's framing was deliberately low-key: Teams is used mainly for everyday back-and-forth, it said, so the impact on actual operations is limited. That is probably true for most of the lost messages, though "limited impact" is the kind of reassurance that lands differently depending on how much you trust the institution offering it.

A "minor" tweak that skipped the safety net

Here is the part that makes IT people wince.

The ministry outsources the operation of this groupware to Toshiba, the long-established Japanese electronics and engineering giant. On April 25, 2026, a Toshiba worker was carrying out an update on the system. The goal was modest: adjusting the settings on the holding area where deleted files sit temporarily before being purged for good, roughly the equivalent of changing how long items linger in a recycle bin.

But the change didn't stay in that holding area. The setting on the live, everyday storage area got altered too, and the data-retention window was effectively rewritten. The result was that messages and files from that nearly three-year stretch were swept out and permanently deleted.

Toshiba's own explanation of why is, in a way, more striking than the error itself. Because the task was treated as auxiliary, just a tweak to a retention-period setting, it never went through internal or vendor review, and the testing beforehand was inadequate. A change small enough to seem unworthy of a second pair of eyes turned out to be big enough to delete three years of a government ministry's communications. The company said it will overhaul its management process, its testing methods and its verification environment to keep it from happening again. MHLW, for its part, said it takes the situation seriously and will require the contractor to follow through on those fixes.

There's no allegation of bad faith here, and a single misconfigured setting is the kind of mistake that has humbled far more than one engineer. But "we skipped review because it looked routine" is precisely the failure mode that change-management procedures exist to catch.

Why "administrative documents" is the part that stings

Strip away the Teams branding and the Toshiba name, and what's left is a more uncomfortable question: a government ministry lost official records, and some of them are unrecoverable.

In Japan, administrative documents aren't just internal memos. They fall under the Public Records Management Act, the 2011 law that governs how official records must be created, kept and eventually disposed of. The principle behind it is accountability: the idea that citizens should be able to trace how decisions affecting them were actually made. Records that vanish can't be checked later, which is why their loss carries weight beyond the inconvenience of a deleted chat thread.

It also isn't MHLW's first brush with missing data. In 2019, the ministry was at the center of a statistics scandal: a key monthly labor survey had been compiled using improper sampling, and, as the Japan Times and others reported, years of underlying records had been discarded that should have been retained under public-records rules. The fallout was enormous: roughly 20 million people had been underpaid in unemployment and other benefits, and the figures had to be corrected. This week's incident is a different beast, an operational accident rather than a methodological cover-up. But it lands on a ministry that already carries a reputation for losing things it was supposed to keep.

For now the practical damage looks contained and the leak risk appears to be zero. The cost that's harder to count is trust: records meant to be permanent turned out not to be.

Public-records management is having a rough decade in a lot of places. From deleted official messaging apps to disappearing emails, plenty of governments have learned that "we'll keep the records" is easier to promise than to engineer. How does your country handle its official records, and would anyone notice if three years of them quietly disappeared?

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